diff --git a/github/GithubIntegration.py b/github/GithubIntegration.py
index 82c85bc9c2..475a6c0f7a 100644
--- a/github/GithubIntegration.py
+++ b/github/GithubIntegration.py
@@ -135,6 +135,7 @@ def get_access_token(self, installation_id, permissions=None):
         headers, response = self.__requester.requestJsonAndCheck(
             "POST",
             f"/app/installations/{installation_id}/access_tokens",
+            headers=self._get_headers(),
             input=body,
         )
 
diff --git a/tests/ReplayData/Authentication.testAppAuthentication.txt b/tests/ReplayData/Authentication.testAppAuthentication.txt
index 53391560e5..9f2a6b2e87 100644
--- a/tests/ReplayData/Authentication.testAppAuthentication.txt
+++ b/tests/ReplayData/Authentication.testAppAuthentication.txt
@@ -3,7 +3,7 @@ POST
 api.github.com
 None
 /app/installations/29782936/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {}}
 201
 [('status', '201 CREATED'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', 'W/"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]
diff --git a/tests/ReplayData/GithubIntegration.testGetAccessToken.txt b/tests/ReplayData/GithubIntegration.testGetAccessToken.txt
index 4f37651d02..a59fe84631 100644
--- a/tests/ReplayData/GithubIntegration.testGetAccessToken.txt
+++ b/tests/ReplayData/GithubIntegration.testGetAccessToken.txt
@@ -3,7 +3,7 @@ POST
 api.github.com
 None
 /app/installations/30614431/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {}}
 201
 [('status', '201 CREATED'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', 'W/"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]
@@ -14,7 +14,7 @@ POST
 api.github.com
 None
 /app/installations/30614487/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {}}
 201
 [('status', '201 CREATED'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', 'W/"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]
@@ -25,7 +25,7 @@ POST
 api.github.com
 None
 /app/installations/30614431/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {}}
 201
 [('status', '201 CREATED'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', 'W/"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]
diff --git a/tests/ReplayData/GithubIntegration.testGetAccessTokenForNoInstallation.txt b/tests/ReplayData/GithubIntegration.testGetAccessTokenForNoInstallation.txt
index db1f2cb827..885a873697 100644
--- a/tests/ReplayData/GithubIntegration.testGetAccessTokenForNoInstallation.txt
+++ b/tests/ReplayData/GithubIntegration.testGetAccessTokenForNoInstallation.txt
@@ -3,7 +3,7 @@ POST
 api.github.com
 None
 /app/installations/40432121/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {}}
 404
 [('status', '404 NOT FOUND'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', '"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]
diff --git a/tests/ReplayData/GithubIntegration.testGetAccessTokenWithExpiredJWT.txt b/tests/ReplayData/GithubIntegration.testGetAccessTokenWithExpiredJWT.txt
index 0ce4c84770..a0dec1f65a 100644
--- a/tests/ReplayData/GithubIntegration.testGetAccessTokenWithExpiredJWT.txt
+++ b/tests/ReplayData/GithubIntegration.testGetAccessTokenWithExpiredJWT.txt
@@ -3,7 +3,7 @@ POST
 api.github.com
 None
 /app/installations/30614431/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {}}
 401
 [('status', '401 UNAUTHORIZED'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', 'W/"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]
diff --git a/tests/ReplayData/GithubIntegration.testGetAccessTokenWithInvalidPermissions.txt b/tests/ReplayData/GithubIntegration.testGetAccessTokenWithInvalidPermissions.txt
index a9b790c55e..216ece9113 100644
--- a/tests/ReplayData/GithubIntegration.testGetAccessTokenWithInvalidPermissions.txt
+++ b/tests/ReplayData/GithubIntegration.testGetAccessTokenWithInvalidPermissions.txt
@@ -3,7 +3,7 @@ POST
 api.github.com
 None
 /app/installations/30614431/access_tokens
-{'Authorization': 'Bearer jwt_removed', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
+{'Authorization': 'Bearer jwt_removed', 'Accept': 'application/vnd.github.machine-man-preview+json', 'User-Agent': 'PyGithub/Python', 'Content-Type': 'application/json'}
 {"permissions": {"test-permissions": "read"}}
 422
 [('status', '422 UNPROCESSABLE ENTITY'), ('server', 'Github.com'), ('date', 'Mon, 24 Oct 2022 23:11:45 GMT'), ('content-type', 'application/json; charset=utf-8'), ('connection', 'keep-alive'), ('content-length', '1962'), ('etag', 'W/"b11a1c9caabe35f1de0a13e597a3022d27d2bff0694c2ccb5a65edc3b4d18837"'), ('cache-control', 'public, max-age=60, s-maxage=60'), ('vary', 'Accept'), ('x-github-media-type', 'github.v3; format=json'), ('access-control-expose-headers', 'ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset'), ('access-control-allow-origin', '*'), ('strict-transport-security', 'max-age=31536000; includeSubdomains; preload'), ('x-frame-options', 'deny'), ('x-content-type-options', 'nosniff'), ('x-xss-protection', '0'), ('referrer-policy', 'origin-when-cross-origin, strict-origin-when-cross-origin'), ('x-github-request-id', "E475:53DD:8B7A89E:11E38A79:63571BB0"), ('vary', 'Accept-Encoding, Accept, X-Requested-With'), ('content-security-policy', "default-src 'none'")]