What is .gradle/caches/user-id.txt file? It seems to be updated on every execution, and it defeats Travis cache


There’s a small file in .gradle/caches/user-id.txt (and .gradle/caches/user-id.txt.lock), and Gradle updates the file on each execution.

Unfortunately, the content changes, so Travis caching treat the cache as modified and uploads it.

What is the purpose of the file and is there a way to make it stable?