http://viper.lbl.gov:8080/cctbx.xfel/index.php/2017_dials.stills_process
Adding some more resources courtesy of @phyy-nx. Aaron says the good stuff is mostly in the papers:
Preprint: https://doi.org/10.1101/2025.05.04.652045
Old newsletter article: https://cci.lbl.gov/publications/download/CCN_2019_p22_Brewster.pdf
Even older newsletter article: https://cci.lbl.gov/publications/download/CCN_201
However, this wiki page (linked above by @kzielinski) is still pretty good:
http://viper.lbl.gov:8080/cctbx.xfel/index.php/2017_dials.stills_process
And then merging is here: