Creator: None (system-internal Symbol).
This Tag is used to mark a 'require_' Tag with an offer that may satisfy the requirement.
The first argument of an !offer Tag should always be the !require tag. The remaining arguments can be whatever is appropriate and should be documented in the description of the require_ symbol.
This is similar to !provide, but where !provide means that the requirement has been met, this symbol just means that it might be able to meet it. Several offers may be made on a require_ Tag before one of them is chosen and used with !provide.