Polkadot Multisig is created by the Signet team, an enterprise-focused team at Talisman.
Talisman is a fully-on-chain organization that runs its operations across Polkadot and Ethereum, including running the largest nomination pools on Polkadot, and coordinating a decentralized workforce of contributors that help to provide support to users.
Polkadot Multisig was originally created because Talisman realized the tools to build businesses in Polkadot lagged behind what was available in Ethereum and set out to build a solution.