Created attachment 613414 [details] freqtweak-9999.ebuild Freqtweak is now at github, as said on main page, and ported to wxGTK-3. Probably best tool for realtime spectral editing. May need some more work to filter out own CFLAGS, but I guess such flags could be good in certain cases (things like -funroll-loops etc).
Can't find any trace of it in gentoo.git, package seems to live in proaudio overlay.
Right, it was certainly in proaudio. In bug with request to remove it https://bugs.gentoo.org/336160 logs clearly tell it's from this overlay.