Good job you found that!Language packs, dictionaries, OpenSearch providers, lightweight themes, and add-ons that only support Thunderbird or SeaMonkey aren’t considered legacy.
My SM and T/Bird themes are Type 32s (multi package install) not the usual Type=4 and that's because to do the content scrolls I had to bundle them in an extension and that's because at the time Mozilla decided that themes couldn't use the override command in chrome.manifest, but extensions can. However, upload them and the validator complains that the extensions are not signed, even though they don't need to be for SM and T/Bird, that's because the validator on AMO is totally ******. Am I boring anyone? The way around it, after talking with Jorge, is to add Firefox to the install.rdfs of the scrolls extensions and get them signed, even though they didn't need to be.
Looking at the above, I reckon come 53 those scroll extensions are going to blow up and reject, just because they include compat for Firefox.
'Luckily' override is now accepted in chrome.manifest for themes, so the solution will be to use it, add scrollbars.css to the theme and ditch the scroll extensions completely and swing to Type=4 only themes and upload. Sorted.
As you can see, unlike AMO, the Frank House does indeed run like a fine tuned machine.
Edit (46 minutes after above post) - both themes now done, both are now totally independent of Firefox and both have been uploaded to AMO and are 'awaiting review'.
Yeah, this has been a glimpse of what a real themer does - yep, we do work quick, yep, the stuff is pretty complicated, but that's half the fun...and, yep, it did annoy Complete Theme writers for 5 minutes when Mozilla called Personas 'themes' (I can make one from start to finish in 10 minutes) and called the guys who churned them out, 'themers'.
But, once you realise that Mozilla were deliberately trying to annoy us by doing that...it no longer was annoying and we knew all along what a real theme author is anyway.