The board
Who has been down there, and what they carried back out. Checked by your own computer, not by anybody else's.
A board is not a service and there is no central one. Each node keeps the
records of delves it was part of and serves them at /board, so a
board is simply what that machine witnessed. Several can be merged, because
two people who were both there hold the same delve with different signatures
on it, and between them the picture is fuller than either had alone.
How this page gets its records depends on where it is. Served from a node, it reads that node. Published on a website, it reads them out of a public repository the client pushes to after every delve, because a page served over https is not allowed to fetch from a laptop with no certificate and no amount of arranging changes that. Nothing has to be redeployed for the numbers to move: the page fetches, the repository is what changed.
Nothing here is asserted. Your browser recomputes each address from the two public keys it was handed, verifies every signature against the exact bytes that were signed, and counts only what survives. If you disagree with a number here, you are right and the number is wrong, because you can redo the arithmetic yourself and this page cannot stop you.
Only delves where somebody else was present and on air are counted, because you cannot witness your own loot, and being reachable over the internet is not the same as having been somewhere.
What is counted
An address is six hex characters derived from both halves of a person's identity, so a record cannot carry an invented signing key beside a real address: the address would not come out right, and the address is what the roster names. Every signature here was checked against a key whose hash matches the name it is standing next to.
A delve counts as cleared for you if the room was cleared, at least one other person signed for it, and both of you were heard on air. Items shown are the ones you walked out carrying, from delves that pass the same test.
There is nothing to stop somebody else publishing a different board from a different set of records, and it would be no less true. This one is only what one node happened to witness.