Got it, thanks.
Primarily, I was not sure if "3rd party services" were limited to the alernative bridges or not.
After carefully reviewing the wording, "HIVE supply on HE" might as well be HIVE held by @honey-swap minus SWAP.HIVE held by the bridges as that is actually the part of the SWAP.HIVE circulation supply that the market wants to be kept outside HE markets.
I mean, it is not like you can inflate SWAP.HIVE supply by interacting with those 20k HIVE held by Beeswap.
To confuse it further, if someone adds up all the SWAP.HIVE (both liquid and in LPs) it should match HIVE assets on @honey-swap and that's a slightly different figure again (probably the one most people assume to be represented by the graph, although I can see that this view sounds imprecise).
BTW, do you think you could track alternative bridges' performance based on profit generated? It might be tricky since it is no longer equal to "fees collected" ever since the main players switched to dynamic pricing.