The Pile

Files tucked inside transactions. The transaction that writes one exists only to do that, so all of it counts — about half is the file, half is the wrapper around it.

Counted

The whole transaction that writes an inscription

When an inscription is moved: the inscribed UTXO going in, and the one it becomes

Not counted

The transaction before it. Every inscription needs a setup transaction first. It looks like a normal payment, so nothing identifies it. This is the biggest thing we miss

The rest of a move. Fees and change. A transaction moving an inscription might be doing ordinary business too, and there is no way to tell

OP_RETURN inside it. Counted under OP_RETURN instead, so it is never counted twice

Bitcoin's built-in slot for attaching data to a transaction. An OP_RETURN output can never be spent — anything sent to one would be burned, so in practice nothing is. None of it is money.

Counted

Every OP_RETURN output on the chain, at the size a node stores it

Not counted

The rest of the transaction. It is usually moving money too

The one in every coinbase. That is protocol bookkeeping, not data someone added

Every inscription sits on a UTXO worth a few hundred satoshis. That is less than the fee to spend it, so it never moves — and every node keeps it in the UTXO set, forever.

Counted

Inscription UTXOs of 1,000 satoshis or less

Not counted

Change sent back to whoever made the inscription. That is normal money

UTXOs that merely descend from one. Being downstream of an inscription does not make a UTXO an inscription

Change is counted under Inscriptions but not here. That is on purpose: the inscription caused those bytes to be written, so they count there — but the UTXO itself is money and will be spent, so it is not a permanent burden on every node.