git ability

hello,

does git have the ability to handle a repository on a removable disk?

here is the experience I had:

I have a project that I manage on a removable disk (therefore with a
".git" directory on it).

until now I did "commits" and "push" on the server from windows10.

I made changes to the source and made a "commit" from linux (on the
same computer). Git asked me again for my username (email and user
name): I then thought that these were not stored in the ".git"
directory

I then saw a new branch called "linuxcompatibility" appear.

I would like to understand.

I thought to myself that I would then merge the "linuxcompatibility"
branch to the "master" branch and push it all back to the server.

if that went well with me, on the server the branch
"linuxcompatibility" remained.

how to get rid of it: nothing seems indicated in the documentation.

Thanks for any clarification