In a solution to my earlier query, Murch used the time period: incremental relay feerate.

On first, I believed that is the identical as minimal relay price (minRelayTxFee) – minimal feerate (sat/VB) that transaction should have with the intention to be included in mempool and relayed. My conclusion was based mostly on the truth that BIP125 is utilizing that time period. Cite:

The substitute transaction should additionally pay for its personal bandwidth at or
above the speed set by the node’s minimal relay price setting.

Nonetheless, the Bitcoin Core documentation associated to RBF makes use of the time period incremental relay feerate for a similar situation. Cite:

The extra charges (distinction between absolute price paid by the
substitute transaction and the sum paid by the unique transactions)
pays for the substitute transaction’s bandwidth at or above the speed
set by the node’s incremental relay feerate.

Identical documentation additionally talked about:

The incremental relay feerate used to calculate the required
extra charges is distinct from -minrelaytxfee…

So, my query is what’s the incremental relay feerate and the way is that tied (whether it is) with the minimal relay price?

Thanks!