diff --git a/src/index.ts b/src/index.ts
index 3702827..759e852 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,7 +1,7 @@
 import { readFile } from 'fs/promises';
 import MagicString from 'magic-string';
 import type { Plugin } from 'rollup';
-import { collectGmApi, getMetadata } from './util';
+import { collectGrants, getMetadata } from './util';
 
 const suffix = '?userscript-metadata';
 
@@ -25,7 +25,7 @@ export default (transform?: (metadata: string) => string): Plugin => {
     },
     transform(code, id) {
       const ast = this.parse(code);
-      const grantSetPerFile = collectGmApi(ast);
+      const grantSetPerFile = collectGrants(ast);
       grantMap.set(id, grantSetPerFile);
     },
     /**
diff --git a/src/util.ts b/src/util.ts
index 00319eb..8106fea 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -2,46 +2,40 @@ import { AttachedScope, attachScopes } from '@rollup/pluginutils';
 import { Node, walk } from 'estree-walker';
 import isReference from 'is-reference';
 import type { AstNode } from 'rollup';
+import type { MemberExpression } from 'estree';
 
-const gmAPIs = [
-  'GM_info',
-  'GM_getValue',
-  'GM_getValues',
-  'GM_setValue',
-  'GM_setValues',
-  'GM_deleteValue',
-  'GM_deleteValues',
-  'GM_listValues',
-  'GM_addValueChangeListener',
-  'GM_removeValueChangeListener',
-  'GM_getResourceText',
-  'GM_getResourceURL',
-  'GM_addElement',
-  'GM_addStyle',
-  'GM_openInTab',
-  'GM_registerMenuCommand',
-  'GM_unregisterMenuCommand',
-  'GM_notification',
-  'GM_setClipboard',
-  'GM_xmlhttpRequest',
-  'GM_download',
-];
 const META_START = '// ==UserScript==';
 const META_END = '// ==/UserScript==';
+const GRANTS_REGEXP = /^(unsafeWindow$|GM[._]\w+)/;
 
-export function collectGmApi(ast: AstNode) {
+export function collectGrants(ast: AstNode) {
   let scope = attachScopes(ast, 'scope');
   const grantSetPerFile = new Set();
   walk(ast as Node, {
     enter(node: Node & { scope: AttachedScope }, parent) {
       if (node.scope) scope = node.scope;
+
+      if (
+        node.type === 'MemberExpression' &&
+        isReference(node, parent)
+      ) {
+        const fullName = getMemberExpressionFullNameRecursive(node);
+        const match = GRANTS_REGEXP.exec(fullName);
+        if (match) {
+          grantSetPerFile.add(match[0]);
+
+          this.skip();
+        }
+      }
+
       if (
         node.type === 'Identifier' &&
         isReference(node, parent) &&
         !scope.contains(node.name)
       ) {
-        if (gmAPIs.includes(node.name)) {
-          grantSetPerFile.add(node.name);
+        const match = GRANTS_REGEXP.exec(node.name);
+        if (match) {
+          grantSetPerFile.add(match[0]);
         }
       }
     },
@@ -52,6 +46,29 @@ export function collectGmApi(ast: AstNode) {
   return grantSetPerFile;
 }
 
+function getMemberExpressionFullNameRecursive(astNode: MemberExpression): string | null {
+  if (astNode.property.type !== 'Identifier') {
+    return null;
+  }
+
+  switch (astNode.object.type) {
+    case 'MemberExpression': {
+      const nameSoFar = getMemberExpressionFullNameRecursive(astNode.object);
+      if (nameSoFar == null) {
+        return null;
+      }
+
+      return `${nameSoFar}.${astNode.property.name}`
+    }
+    case 'Identifier': {
+      return `${astNode.object.name}.${astNode.property.name}`;
+    }
+    default: {
+      return null;
+    }
+  }
+}
+
 export function getMetadata(
   metaFileContent: string,
   additionalGrantList: Set<string>,
diff --git a/test/util.test.ts b/test/util.test.ts
index 1559a53..c98e11a 100644
--- a/test/util.test.ts
+++ b/test/util.test.ts
@@ -1,23 +1,84 @@
+import { parse as parseCode } from '@babel/parser';
 import type { AstNode } from 'rollup';
-import type { EmptyStatement } from 'estree';
 
 import {
-    collectGmApi,
+    collectGrants,
     getMetadata
 } from '../src/util';
 
-describe('collectGmApi', () => {
-    const EMPTY_STATEMENT: EmptyStatement = {
-        type: 'EmptyStatement'
-    };
-    
-    it('should return an empty set on an empty input', () => {
-        expect(collectGmApi(EMPTY_STATEMENT as AstNode).size).toBe(0);
-    });
+describe('collectGrants', () => {
+  const parseCodeAsEstreeAst = (code: string) => {
+    const file = parseCode(code, { plugins: ['estree'] });
+    return file.program as AstNode;
+  };
+
+  it('should return an empty set on an empty input', () => {
+    const astNode = parseCodeAsEstreeAst(``);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(0);
+  });
+
+  it('should return only GM_dummyApi', () => {
+    const astNode = parseCodeAsEstreeAst(`GM_dummyApi`);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(1);
+    expect(result).toContain('GM_dummyApi');
+  });
+
+  it('should ignore any scope-defined variables that look like GM APIs', () => {
+    const astNode = parseCodeAsEstreeAst(`
+      let GM_dummyApi;
+      GM_dummyApi;
+    `);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(0);
+  });
+
+  it('should return only GM.dummyApi', () => {
+    const astNode = parseCodeAsEstreeAst(`GM.dummyApi`);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(1);
+    expect(result).toContain('GM.dummyApi');
+  });
+
+  it('should return unsafeWindow when presented with just unsafeWindow', () => {
+    const astNode = parseCodeAsEstreeAst(`unsafeWindow`);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(1);
+    expect(result).toContain('unsafeWindow');
+  });
+
+  it('should return nothing unsafeWindow when presented with unsafeWindowButNotReally', () => {
+    const astNode = parseCodeAsEstreeAst(`unsafeWindowButNotReally`);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(0);
+  });
+
+  it('should return unsafeWindow even when a subfield is accessed', () => {
+    const astNode = parseCodeAsEstreeAst(`unsafeWindow.anotherThing`);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(1);
+    expect(result).toContain('unsafeWindow');
+  });
+
+  it('should return unsafeWindow even when a subfield is accessed with object notation', () => {
+    const astNode = parseCodeAsEstreeAst(`unsafeWindow["anotherThing"]`);
+    const result = collectGrants(astNode);
+
+    expect(result.size).toBe(1);
+    expect(result).toContain('unsafeWindow');
+  });
 });
 
 describe('getMetadata', () => {
-    it('should throw error on an empty input', () => {
-        expect(() => getMetadata('', new Set())).toThrow(Error);
-    });
-});
\ No newline at end of file
+  it('should throw error on an empty input', () => {
+    expect(() => getMetadata('', new Set())).toThrow(Error);
+  });
+});