all the secrets lie in the bytes if you look under the hood!
as the other poster said these are Omni layer transactions. the way to recognize them is first their OP_Return output which you would see as a red text on blockchain.com saying "Unable to decode output address" but looking under the hood you could see the output is this:
6a146f6d6e69000000000000001f0000000e45c3c500
the initial 4 bytes being 6f6d6e69 is an indicator of Omni
in case you are more interested:
6f6d6e69 Omni marker
0000 version
00000000001f tether marker
0000000e45c3c500 amount = 61,300,000,000