chain.so block explorer might have blocks 663043, 660903, 655191

[0xB10C]

Chain.so returns an error for the following stale block hashes. Normally, chain.so doesn't return an error but redirects to the main page for blocks that are not found. This could indicate they have these blocks. However, API access seems to be very expensive. No free tier available.

• https://chain.so/block/BTC/000000000000000000019a6273252cd334c21baf6cbf727bb3d3e23fe44dbaf1 (663043)
• https://chain.so/block/BTC/0000000000000000000d84896f7e9ad2c29da4c8bf0766cb167ca7e73e5535b9 (655191)
• https://chain.so/block/BTC/000000000000000000095fe6785b8572b933b9d9fda4649cbe33068e743a714c (660903)

[deadmanoz]

So 2 of the three have since been filled, neither from chain.so:

• 655191: added by @reardencode in add my stale blocks #76 (Feb 2026)
• 663043: added by @guggero in add: 4 block files and 2 headers #138 (Sep 2026)

Both check out as valid stales, including UTXO context and script verification.

660903 is still header-only. ViaBTC mined it, merge-mined with Emercoin, RSK and Syscoin:

https://mmm.deadmanoz.xyz/?tree_height=660903&selected=000000000000000000095fe6785b8572b933b9d9fda4649cbe33068e743a714c

The Syscoin AuxPoW gives us its full coinbase and the coinbase's merkle branch, which folds to the header's merkle root. Unfortunately it is not a body though 😦