(Hmph. The list of projects seems to force this to "MobileFrontend-Feature-requests", but I consider it a bug report.)
When I use my smartphone (Samsung Verizon Android Galaxy S-3, model SCH-I535, OS v4.4.2) to access the Mobile β Frontend, without experimental features, talk pages have no TOC. That's seldom an issue on article talk pages, but there are a few talk pages that I access quite frequently on which I really, really need a better way to find a specific section than swiping my finger up or down the screen as fast as possible. Half the time this leads to overrunning the section without seeing it as it zips by at, apparently, about 0.3c. And half the time I accidentally press on a link as I move the page. (Not "the other half of the time": sometimes I get both f*ck*ps, and sometimes neither.) One of these pages is my own talk page.
The page has __TOC__ on it, and it works fine on the desktop frontend, but it's impotent on the mobile. (See [[ URL | w:Wikipedia:Teahouse/Questions#mobile-beta-talk-TOC ]].) ISTM that I should have the choice of seeing or not seeing the TOC on my own talk page. Ergo, this is a bug report.