Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution. PrairieLearn's Contributor License Agreement.
We use cla-assistant/github-action to check for and store signature information. The signature information can be found in this repository in the signatures.json file.
Some folks who contributed before the CLA was established were contacted via email and asked to sign the CLA. Their signatures can be found in the emails directory.