After updating to Docker Desktop 4.15.0, it added
source /Users/<username>/.docker/init-bash.sh || true # Added by Docker Desktop
to my .zshrc. It also created .config/fish/config.fish, .bash_profile and .bashrc with the same line.
The bin folder is currently empty, which makes this even more suspicious.
I consider this bad behavior. Apps are not supposed to change my $PATH without at least telling me or mentioning it in the Release Notes.