Understanding RBF and Full RBF

I was checking the mempool lately since I heard it's getting pretty congested. I noticed some transactions labeled as Full RBF while others just had RBF. Honestly, I can't recollect ever seeing the Full RBF option before. The only thing I know is RBF. So, what's the real difference between these two?

There is no such thing as flagging a transaction as full RBF. Full RBF is a setting for nodes. If a node has enabled full RBF, it allows any unconfirmed transaction to be replaced by a new one paying higher fee, even if the original transaction has not been flagged as RBF.

The only tagged in RBF are simply the opt-in full RBF where the transaction initiator add signals that transaction will be changed in future. This way the nodes may allow it to be changed in future and also it wouldn’t be treated as a complete payment by the recipient. This is Called BIP125 replaceability . The full RBF doesn’t needs to add a signal to the transaction and could change the transaction anytime

Well, I haven't noticed this term earlier in mempool space. Just noticed it yesterday and I tried to figure out what it exactly is but I failed to get the context. It seems to be a term used by mempool. Is it the same one as of Full RBF setting for the node? Can you see the last tx? What it's referring? Thanks and I'm familiar with the RBF term. Check out the image attached above. That's where I'm confused.

It means that the transaction has replaced a transaction which hadn't been flagged as RBF. The other transactions that are shown in the image have replaced transactions that had been flagged as RBF. As I said in my previous post, nodes may allow a transaction to replace another one, even if the original transaction has not been flagged as RBF.

Here's a thread I opened a while back discussing Full RBF: https://bitcointalk.org/index.php?topic=5403730.0 Here's the post on the mempool.space GitHub discussing this new RBF ticker: https://github.com/mempool/mempool/pull/3867. It was merged around 2 months ago. The term is used across the Bitcoin ecosystem, not just by mempool.space. It is a setting nodes can apply which means they will accept and broadcast replacement transactions for any transaction in their mempool, regardless of whether the original transaction is opted in to RBF or not. Here's an example transaction: https://mempool.space/tx/5bbea8b183b7e67cd75d54604dd19e0724b89e2b8675133f0feec360f0fd497e Mouse over the first transaction in the "RBF History" box, paying 9.24 sats/vbytes. You'll see it was not opted in to RBF. And yet it has been successfully replaced anyway by a new transaction paying 10.2 sats/vbyte. This is what is meant by full RBF. Any node with full RBF enabled will accept replacements for any transaction in their mempool.