Are egg-less pasta typically made with durum flour?
This answer is valid only for what I can call Italian type pasta.

The best then is to use durum as it is characterized by a high content in protein, specifically those of the gluten group. Proteins changes upon cooking results in a reticulated structure that retains starch and gives the typical "al dente" feature as well as resistance to overcooking.

An Italian law* promulgated 1967 qualified as pasta only the products obtained from durum and having a proteic content of at least 12%.

More recently, globalisation oblige?, the law* has been modified as to allow wheat to be mixed with durum up to 3%.

According to the info labels, top pasta producers are still using durum and nothing else.

The above does not concerns regional specialities that only resembles pasta (they are indeed pastasciutta but this term refer to the dish) but go called by their specific names, both colloquially and commercially (for instance they might contain buckwheat, chestnut flour, potatoes, etc., examples are pizzoccheri and various types of trofie and dumplings).

*I don't post links to the Gazzetta Ufficiale, the official laws collection as it's obviously in Italian

This link has a table that should be readable to those reading English http://www.pasta.it/legge.htm

Points 4 and 5 deals with wheat, forbidding it as the only ingredient and allowing it within the above mentioned limit of 3% in certain types of pasta.