It’s “probably” (not sure, just a guess) the cost of the token creation. Everything on Solana is a token. Classic nfts (not compressed ones), AMM-LP tokens, all tokens and coins (PYTH, JUP, BONK, WEN, USEDCAR, BODEN, or whatever coin), tokenised interactions with apps (like votes, on-chain profile creations, etc). If this is the case, you can check sites/tools like “sol-incinerator” and try and find the respective token created for your address.
Wait for more answers on your question and excersice caution with everything.