Android Studio file names appearing in blue color

The blue color refers to git integration. The docs say the files are in blue, that have changed since last check-in.

Most of SO's rules are based on Google SEO, so I have to add here that there are other colors that mean other things. If I do not, someone will come along and say that my answer does not meet guidelines and specifications.

Gray
Deleted File is scheduled for deletion from the repository.

Blue
File has changed since the last synchronization.

Green
File is scheduled for addition to the repository.

Violet
File is merged by your VCS as a result of an update.

Brown
File exists locally, but is not in the repository, and is not scheduled for adding.

Olive
File will be ignored in any VCS operation.

Light brown
File is modified without checkout. This status is valid for the files under Perforce, ClearCase and VSS.

Red
During the last update, file was merged with conflicts.

Lilac
File is deleted locally, but was not scheduled for deletion, and still exists in the CVS repository.

Dark cyan
The file is taken from a different branch than the whole project. This status is valid for CVS and SVN.

Here is the referenced documentation.

https://www.jetbrains.com/help/idea/2016.3/file-status-highlights.html