OP's question is technically right, but it's not Bitcoin specific.
D = dogecoin addresses
m = testnet pubkey hash
S = That's a tricky one... The stacks network uses addresses that start with an 'S'. It's the mainnet pay-to-pubkey hash. It's essentially a Bitcoin layer-2 implementation for smart contracts etc. Here is a github post to verify what I am saying: https://github.com/stacks-network/stacks-core/issues/832#issuecomment-400393291
This is actually incorrect, unfortunately. However, this is actually an implementation used by blockchair, and the format is unique to them. Confusion seems to stem from the fact that people think that these are addresses and not representation of scripts on Blockchair.D = dogecoin addresses
m = testnet pubkey hash
S = That's a tricky one... The stacks network uses addresses that start with an 'S'. It's the mainnet pay-to-pubkey hash. It's essentially a Bitcoin layer-2 implementation for smart contracts etc. Here is a github post to verify what I am saying: https://github.com/stacks-network/stacks-core/issues/832#issuecomment-400393291
There are three different types as correctly identified, d-, m-, s-. d- is for OP_return and m- is for multisig and s- is for non-standard script. S- is relevant to that transaction mentioned is because the script is just OP_NOP OP_NOP OP_NOP OP_NOP OP_NOP OP_PUSHNUM_1. Not a standard that Blockchair recognizes, and thus the s- prefix.
There was an FAQ on this previously, but the only reference I can find currently is here: https://github.com/Blockchair/Blockchair.Support/issues/273.
It's something Blockchair made up:
