If a transaction sits a long time in the tezos mempool for a reason or another does it get eventually cleaned-up or will it stay there forever ?
NB: After the adoption of the Granada protocol, which halves the minimal time between blocks, the
max_operation_ttl constant was doubled from
120 blocks, to roughly preserve the length of the live blocks and operations window when measured in wall-clock time.
NB NB After the activation of the Mumbai protocol upgrade further halved minimal blocktime from 30s to 15s, this constant was consequently doubled, again, from
240 blocks to preserve the invariant.