How can I configure the filename → language association?

[parmentelat]

remotely related to this thread:

Defining jupytext as the default viewer for text notebooks under jlab4

I’d like to revisit a discussion that we’ve had a while back already, but today in the context of jlab4 I’m trying to help @mwouts with the jupytext extension for jlab4, and it seems like an alpha version is in sight - https://github.com/mwouts/jupytext/issues/1054 - but at this point there is still the same issue addressed in the post above, namely that double clicking in a jupytext notebook in the file browser opens it in the editor and not as a notebook, and this despite the configuration t…

but going a little further, would there be a way to say something like

• all the files ending in *-nb.md should be opened by jupytext-notebook, while
• all the other files ending in *.md should be opened my markdown-preview

which is what I’d really like to be able to do in the end…

given that the defaultViewers setting maps tools to languages, I guess what I’m looking after is a way to map file naming schemes to languages ?
or is that smarter than that, is there some shallow inspection of the file to kind-of guess the language ?

sorry for asking that many dumb questions…

[parmentelat]

following-up on my own question:

I can see in
jupyterlab/packages/docregistry/src/registry.ts
that a DocRegistry instance has a _fileTypes field populated in my case with 27 entries for text, markdown, notebook, etc…

can I easily control that from some configuration file ?