Saving the theme in the new editor seems to remove some directories

[filipesmedeiros]

It seems that saving a file in the Ghost theme editor removes the .git directory.

To reproduce:

1. Create a theme inside the themes dir and create, inside it, a .git directory (it can be empty)
2. Select that theme in the admin UI (in the "Installed" themes tab
3. Edit it in the theme editor, and save it
4. Go back to the theme dir (and if you try to ls, you can't, for some reason you have to cd .. and cd back into the theme dir) and then ls -A. The .git dir is now gone (but not, for example, the .gitignore, if you have one)

Originally posted by @filipesmedeiros in #27656 (comment)

[filipesmedeiros]

Most likely related: .git does not show up in the editor, while .gitignore does

[sam-lord]

The theme editor makes a zip file on the client side to upload, replacing the server-side version of the theme. On upload of a zip, we check the theme with gscan, which strips unrelated files including the .git folder.

If you want to use Git to work on a theme, then the official Github intergration would be the recommended route!