QM Criterion for Private Use Area Characters (QM v7.0)
Checks whether all Private Use Area characters used in the source and target paragraphs are identical and exist in the same number.
The Private Use Area is a special Unicode area that enables the use of custom characters not standardized in Unicode. These characters must be coordinated between the parties that create them and those who use them. For example, Private Use Area characters can be provided in a jointly used font file.
For this criterion, the filter for similar errors groups errors with the same missing and additional PUA characters.