Firefox build discouraged?

[immwi]

Hi
Thanks for your tool. I work with Firefox and tried to build the extension. I get the following result:

npm install --global web-ext

npm warn deprecated inflight@1.0.6: This module is not supported, and leaks memory. Do not use it. Check out lru-cache if you want a good and tested way to coalesce async requests by a key value, which is much more comprehensive and powerful.

npm warn deprecated @humanwhocodes/config-array@0.13.0: Use @eslint/config-array instead

npm warn deprecated rimraf@3.0.2: Rimraf versions prior to v4 are no longer supported

npm warn deprecated @humanwhocodes/object-schema@2.0.3: Use @eslint/object-schema instead

npm warn deprecated glob@7.2.3: Glob versions prior to v9 are no longer supported

npm warn deprecated eslint@8.57.1: This version is no longer supported. Please see https://eslint.org/version-support for other options.

This looks not very encouraging.
Are there other ways to build the extension or is it doomed for Firefox?
Thanks for your help!
cheers