The logo makes a whole lot of sense for curl, especially given curl's target market. The Mozilla logo is problematic, IMO, because of its target market (the entire Internet userbase) and the fact that the "://" is being used as a kind of l33t-speak for the letters of the brand name. Such an odd decision.

The :// is in fact identical, which is actually a bit weird.

They both use the symbols, but the design is not identical. The curl colon is high off the baseline, while the Mozilla colon is not.

That's bound to happen when a logo is based on something so core to the context.