c6c3ec3149
The `<attach>` element now supports a "frame" attribute, allowing users to specify either a "body" or a "frame" to attach to, but not both. The XML parser has been updated to handle this new attribute and the mutual exclusivity constraint. PiperOrigin-RevId: 941245904 Change-Id: I4c0edeed5f3a9e456aed96c373b1647fe79841d9