If you save your IKEA wrenches from their steel cable "curtain rods," you will have a 2mm hex wrench or two to spare; the 2mm wrenches are used to tighten the pair of set-screws holding each end of the cable into the wall-mounting.
The three sets of metric allen wrenches I'd accumulated over the years did NOT contain that itty-bitty 2mm wrench, and I didn't want to try forcing a torx-fit.
However, when I finally thought to check, I DID have a 2mm hex "screwdriver tip" in a large "universal set" of odd magnetic screwdriver tips--one with things like hollow-pointed torx, hollow-pointed hex, pin tips (imagine a flat-bladed tip with the middle 1/3 removed)--those so-called "tamper-resistant" screw heads (no triangle points, though, for all the kids' toys made in China).
And why hadn't I thought to look in the screw driver set first thing? Because the hex 2mm was a WRENCH, not a screw with a hexagonal driver tip. Talk about limits imposed by "context" or "framing"--and age.