Covenants are a feature proposed for Bitcoin that can place limitations on how coins can be spent. This could be used for example to make it so that you can only send to a few whitelisted addresses from your main wallet (for security). But it's been a controversial proposal because this could also be used for censorship, for example governments requiring that your address have a covenant to blacklist certain addresses.

There have been numerous proposals for soft-forks: OP_CHECKTEMPLATEVERIFY, and the more recent OP_VAULT/OP_UNVAULT