This is not the final website. It is a demo of the real tool working, made for Y Combinator.
AxisRemedy

31-015 The FontDescriptor dictionary of an embedded CID font contains a CIDSet string, but at least one of the glyphs listed in the CIDSet string is not present in the font program.

A CIDFont's CIDSet lists a glyph missing from the font program.

Checkpoint
31: Fonts
ISO 14289-1 (PDF/UA-1) clause
7.21.4.2-4
Test type in the protocol
Machine-testable
Applies to
A single object

How AxisRemedy handles it

Tested by the app. AxisRemedy tests this condition itself. For each document it records passed, failed or not applicable, and for every failure the object and the page.

What the check covers

Decided for TrueType CIDFonts with an Identity CIDToGIDMap.

Repairs that target it

Repairs are optional. The few that could change how a page looks, such as embedding a missing font, need your explicit consent.