The now deprecated FONT FACE attribute was defined as a comma-separated list of names. The entity was needed if you had a font name with a comma in it.
Another comma-separated list is in the TH|TD AXIS attribute which is considered obsolete now. I found two other CSL attributes in APPLET ARCHIVE (depr.) and AREA COORDS but neither of them need a comma entity.
So the comma entity exists only as a historical artifact.
Another comma-separated list is in the TH|TD AXIS attribute which is considered obsolete now. I found two other CSL attributes in APPLET ARCHIVE (depr.) and AREA COORDS but neither of them need a comma entity.
So the comma entity exists only as a historical artifact.