Update ptz-explainer.md

ptz-explainer.md

@@ -103,8 +103,8 @@ if ("tilt" in settings) {
 
 The example below shows how camera pan could be reset when acquiring a
 PTZ camera in `getUserMedia()`. Only ideal constraints are allowed for pan,
-tilt, and zoom constraints. Using mandatory ones will cause the returned promise
-to reject with `TypeError`.
+tilt, and zoom constraints in a basic set. Using mandatory ones will cause
+the returned promise to reject with `TypeError`.
 
 ```js
 const videoStream = await navigator.mediaDevices.getUserMedia({
@@ -195,9 +195,9 @@ signature of the user, that would enable to recognize them later on, even if
 they clear state from their browsers.
 
 1. The immediate failure of a `getUserMedia` call with `TypeError`
-   when using pan, tilt, and zoom mandatory constraints (used with `min`, `max`,
-   and `exact` keywords) makes sure a malicious script can't detect whether a
-   PTZ camera is available on the system without prompting the user.
+   when using pan, tilt, and zoom mandatory constraints in a basic set (used with
+   `min`, `max`, and `exact` keywords) makes sure a malicious script can't detect
+   whether a PTZ camera is available on the system without prompting the user.
 
 1. A malicious website could set pan, tilt, and zoom to minimally different values
    and scoop them later on. To mitigate this, the browser could reset pan, tilt,