git has a way to run scripts, which are invoked by specific git commands. The git hooks are located in <mbed TLS root>/.git/hooks, and as such are not under version control for more information, see the git documentation.
The mbed TLS git hooks are located in <mbed TLS root>/git_hooks directory, and one must create a soft link from <mbed TLS root>/.git/hooks to <mbed TLS root>/git_hooks, in order to make the hook scripts successfully work.
Example:
Execute the following command to create a link on linux from the mbed TLS .git/hooks directory:ln -s ../../git_hooks/pre-push pre-push
Note: Currently the mbed TLS git hooks work only on a GNU platform. If using a non-GNU platform, don't enable these hooks!