Do we want to have the ability (for people who are creating a new instrument without changing ResINS) to insert the new instrument file into INSTRUMENT_MAP? That way, they would be to use Instrument.from_default instead of Instrument.from_file. All we would need to do for this to be possible is to allow INSTRUMENT_MAP entries to also be full paths, which could be done by adding a os.path.exists check to Instrument._get_file.

That seems pretty innocuous. Do you have use case in mind where it wouldn't be convenient to use from_file?

Not in particular, but I suppose it would depend on the circumstances under which someone might want to create a new instrument without opening a PR for us. In a script or jupyter notebook, I don't think it would be difficult to keep a variable with the path to their YAML file around, but for anything more complicated (like software), I imagine it might be easier to register once and then simply call from_default.

I am not sure this is important to have, but I wanted to check in case it is.