For developers that includes version control and package managers, amongst other things.
Do you need to know how git is implemented? Of course not. No more than you need to know how your compiler converts source code to executables.
...but understanding the basics of the tools (eg. what paths and layer groups are, to compare to photoshop), isn't something you can just wave your hands in the air and say 'not my problem'.
Its your job to know this stuff.
For example: in this case, knowing what a branch is, how to create and delete one, and how to merge with one is necessary. Knowing that the branch identifier is a hash, called a "reference" or similar jargon and what that entails, internally, is superfluous and adds pointless complexity: if that's really required then git isn't good. I have more important things to think about as a developer than what internal machinery operates git.
That could be extended to other tools like firewall configuration, TLS setup, library details, logging configuratoin, monitoring, etc. But you won't get very far in fixing any problems if you don't read documentation and investigate further.
It's also kind of silly to call git's terminology "non-standard". Git was the first truly widely used DVCS, so if anything, git's terminology is the standard terminology by definition.
You don't need to know the format of git pack files or the network protocol in order to use git.
You do need to understand the concepts of commits and branches.