ClangPchManager fills up storage with pch files and takes too much CPU

After working with qtbase and qtdeclarative for a while, I ended up with 276 GB in ~/.cache/QtProject/QtCreator/pchs. I generally configure Qt with -no-pch so that I can use icecream, and so that frequent changes to headers do not result in the error that the pch file is out of sync with the header. So I was disconcerted over the last couple of days to see a progress bar in the lower right corner saying that Creator is building PCH files (where are those going, I wondered), and also seeing in top that the process doing that was taking up 400% CPU for a long time, and thereby slowing down my frequent builds. Then this morning it turned out that I'm out of disk space because of that, too: the pch files I don't need are literally taking up 2/3 the space on my entire SSD. (Is there an algorithm in place to delete them when they're outdated?) So I will try to keep that plugin turned off, without knowing the consequences.

It doesn't seem very visible what features in Creator this plugin is needed for. The Description in the Details dialog just says "Clang precompiled header plugin."

It's hidden behind the "Show all" checkbox, too.