I searched around a bit and haven’t found a nickname for it like turbofish for
::<> in Rust or the plethora of names for things in Ruby, like “stabby lambda”
->, “twiddle waka”
I’ve heard it called Paamayim Nekudotayim, literally “twice colon”, from my days in PHP using it as the scope resolution operator there, but an eight-syllable Hebrew phrase can be a little hard to pronounce and is certainly no more convenient than simply saying “double colon” in English.
I mentally call it “double double dots” because of mistranslation years and years ago.
What have you all called it?