The "test-emailblob-refcheck" command:

Usage: fossil test-emailblob-refcheck [--repair] [--full] [--clean]

Verify that the emailblob.enref field is correct.  Report any errors.
Use the --repair command to fix up the enref field.  The --full option
gives a full report showing the enref value on all entries in the
emailblob table.  If the --clean flags is used together with --repair,
then emailblob table entires with enref==0 are removed.