Here are few definitions, which I found, of what "et alibi" means:
And elsewhere; used to terminate lists of passages in a text (link).
In lists of places, et alibi (meaning "and elsewhere") is used in place of etc. (link).
A less common variant on et cetera used at the end of a list of locations to denote unlisted places (link).
And here are few examples of usage:
"[Quote.]" Letter of Philip to the Bishop of Arras, (February 12, 1559,) ap. Papiers d'État de Granvelle, tom. V. p. 454, et alibi (link).
Casparis Barlæi, rerum per octennium in Brasilia et alibi nuper gestarum, sub præfectura illustrissimi Comitis I. Mauritii, Nassoviæ, &c. comitis, nunc Vesaliæ gubernatoris & equitatus fderatorum Belgii ordd. sub Auriaco ductoris, historia (link).
As I understand from these examples, et alibi can be used in both cases:
To refer to unlisted places in the text (p. 454, et alibi)
... As well as a reference to unlisted geographical locations (Brasilia et alibi)
Is it correct assumption? (It was the first part of the question).
Also, what does the 1st example actually mean? "Tom. V. p. 454, et alibi" - how it could be translated to simple words of modern English? I can't understand (see the comments).