Where can I find a list of CheckIDs for sp_Blitz? We have a home-grown system of monitors and processes that generate events which are then gathered into a central instance and are sent as daily summary reports to operational DBAs via SSRS.  It reports on anything from non-standard configuration, missing backups, disabled jobs that shouldn't be, databases in bad states, mirroring and AG issues, audit related issues (SOX), etc.

One of the things I am currently doing is writing a process that runs sp_Blitz on a weekly basis and generates events based on some of the findings.

Brent Ozar mentions that an Excel file with all of the possible CheckIDs is contained in the First Responder Kit download, and I can't find it in there.  There is also a link on the sp_Blitz page that is supposed to link to it, but it points to a non-existent page on GitHub (I get a 404).

Does anyone know where I can find this document that contains every possible CheckID and its description?
Sure, it's in Markdown here: https://github.com/BrentOzarULTD/SQL-Server-First-Responder-Kit/blob/master/Documentation/sp_Blitz_Checks_by_Priority.md

If you find any inconsistencies with it, check out the Contributor Guide for how to open issues in the GitHub repo, discuss the changes you want to make, and check in changes.