This is useful for claiming pegins with elements

gettxoutproof ["txid",...] ( "blockhash" )

Returns a hex-encoded proof that "txid" was included in a block.

NOTE: By default this function only works sometimes. This is when there is an
unspent output in the utxo for this transaction. To make it always work,
you need to maintain a transaction index, using the -txindex command line option