What kind of inscription is this?

I'm doing a research project on Ethereum inscriptions and blobs, when I found about 2500 transactions with the following format:

18.5 usdt(matic) -> 18.216868 usdt(bsc) fromhash: 0xc16d54f5754aadef9ebfc959ac252a92d50343017e3c9cc4133b4b423c7021a1 tohash: 0xdfbeb1d5cd01459d61d5b242fbf8efc69ea141951b96c8d6be3e3ba04ed3d0ca 5.85 eth -> 45.06472 bnb(bsc) fromhash: 0x5734f607fd4ed5e0d37e8f6774faf331a6985a1574d67c5a0b52d7bd94f6d7b9 tohash: 0x26776da327f522b636fac41112b08d90bb3e466c984183d88f4402d145c4d374 10.165616 eth -> 18611.996123 usdt(tron) fromhash: 0x25bca2044ad8f7889f94e4161abdc440f2538034685d89eaf390669bef7006fd tohash: 66cd1adde66f1b4096fe61afa411bea1adfa91b9acd9f39bca7b0767523d3baa 

They look like some kind of L2 or off-chain solution for token transfers.

These transactions have become more prevalent recently

https://preview.redd.it/arhohwgsu3sd1.png?2744&format=png&auto=webp&s=a4bf8c1a70347469f6882711be7649ee292419c8

Most of these were created by two EOAs: 0xa15ede0cf46c12e4a79632df33ba1b2f428e5d15 (1600 messages) and 0x8e3e5eec92c401d26b9e5eb17cba828772736558 (1300 messages).

Does anyone know why these inscriptions have this format? Are they related to some project?

Btw, here is the Dune query I used:

SELECT block_time, block_number, gas_used, 'from', to, FROM_UTF8(data) AS msg FROM ethereum.transactions WHERE success = true AND value = 0 AND position('fromhash:' IN from_utf8(data)) > 0 AND position('tohash:' IN from_utf8(data)) > 0 SELECT block_time, block_number, gas_used, 'from', to, FROM_UTF8(data) AS msg FROM ethereum.transactions WHERE success = true AND value = 0 AND position('fromhash:' IN from_utf8(data)) > 0 AND position('tohash:' IN from_utf8(data)) > 0