I'm always eager to read these progress reports. It is amazing how interesting it is to read about the kind of bugs they face, and how they were diagnosed and fixed. Can anyone recommend other open source projects that do this sort of writeup?

PCSX2, the PS2 emulator has recently started doing this. mGBA has also been creating some excellent writeups.[1]

https://endrift.com/mgba/2015/06/27/cycle-counting-prefetch/

First Exploration-ship with ulifted clients launches towards shallow cluster?