The interpretation of a string of addresses separated by commas and/or
semicolons was already defined in the v1 man page for ed.

Ed was essentially a stripped-down version of Multics qed. The latter
was originally
written by Ken. Unfortunately the "Multics Condensed Guide" online at
multicians.org describes how strings of addresses were interpreted
only by canonical examples for the various editing requests.

I  have no specific memory of semicolons in qed. I have a vague
recollection that semicolons originated in ed, however you should put
no trust in this. Maybe Ken remembers.

Doug