An explanation of why 404 errors for language JSON files may appear in the developer console from q2-tecton-sdk.
Sometimes you may see 404 Not Found errors in the console on GET calls for en-us or other language JSON files.
This is the running extension checking to see if language file assets have been deployed that it should use with the loc functionality. It is checking for files either deployed with the extension or customizations that could be deployed via Q2 Config. Right now, the only way for the running extension to know if there are string customizations is try to GET the assets from known locations and naming conventions.
This error is benign unless you actually have deployed language files that are not being found.
If you are expecting language files, you may need to check that your language files are correctly output into your dist folder at build time or that customizations made via Q2 Config string editing are being built and deployed correctly.