When I click on "Import tracker data" but I forget to select a file I get an opaque 400 error instead of a more descriptive message such as (example) "No file selected for import". See screenshot: https://upload.disroot.org/r/GD0pb9W0#/njxDQ2NUlCQ2W6KnF4+4VZVwc8VhGX8BCGC3FTO/PM

Same error when trying to upload any other file than a gzipped file

Discussion: https://lists.sr.ht/~sircmpwn/sr.ht-discuss/%3C87edyzy4pb.fsf%40city17.xyz%3E