See changes in Android Support Library sources bet

I want to clone repository for Android Support Library and see what has been changed between version 24.1.1 and 24.2.0.

I know that repository is located here but:

Its latest commits are dated by July 1 though latest support library release 24.2.0 was in August.
There are no tags like support library versions 24.1.1, 24.2.0, etc.

How can I just see what commits were made between versions 24.1.1 and 24.2.0?

There are tags (android/platform_frameworks_support/releases), but they are specific to the android/platform_frameworks_support repo.

The Support Library Revision History does mention 24.x.y revisions, and it says the v4 support librairies have been splitted in modules like support-compat.
You can see one of those modules in dandar3/android-support-compat which mentions being it based on ANDROID_SDK/extras/android/m2repository/com/android/support/support-compat/24.2.0/support-compat-24.2.0.aar

So we are talking about a completely different set of git repositories:
See dandar3/android-support-README.

So pick any of those support repos, and see what has changes between two tags.
You can do it directly on GitHub:

https://github.com/dandar3/android-support-v4/compare/24.1.1...24.2.0

The Book "Gradle for Android", from Kevin Pelgrims, mentions:

New Android projects have a dependency on the Android Support Library by default.
When installing the Google repositories using the SDK manager, two Maven repositories are created on your hard drive:

ANDROID_SDK/extras/google/m2repository

ANDROID_SDK/extras/android/m2repository

This is where Gradle gets the libraries provided by Google, such as the Android Support Library and Google Play Services.

Again, the sources (as Git repos) might not be available, but you still can get those projects through the SDK Manager.