The main repo page is here. The docs for individual modules (for the latest stable release) are:
The current code also has Javadocs available on JitPack.io, if JitPack has built the latest version. You might need to go to one of these pages or try to build with the latest commit before these links work. You can try depending on the latest version listed in Commits here, or just depend on a module of your choice with Gradle or Maven. That could use:
implementation 'com.github.yellowstonegames.SquidSquad:squidcore:-SNAPSHOT'
In any of your Gradle files' dependencies blocks, which would force JitPack to build the latest library and docs when your project import or build starts. It can take a while to complete.
In any of the following links, you can change -SNAPSHOT to any commit hash JitPack has already built (likely one you already depend on). That allows you to get a known exact version's docs from JitPack, even if it isn't a release.