The final version of proposal at Village Pump Policy has been open for approximately 25 days and has received unanimous support (12 "supports", 0 neutrals, 0 opposes). The exact proposal was/is:
"When the the administrator who made a block subsequently determines that the block was in error, let's create the ability and expectation that that administrator can and will mark the block as being in error in a way that makes it very clear. This can be via a mark on that block itself, or the ability to create an additional log entry (without creating an additional block) This ability to mark the log shall only be used by an admin to mark their own block as being in error. The "expectation" will be created by some new wording in Wikipedia:Blocking policy. The idea of a system for the community to do this without agreement by the blocker is acknowledged and can be discussed later but (for simplicity) is not included in this proposal."
Could you implement this? If it is possible to make it so that when this feature is used a message comes up that says "This feature is to be used only by an administrator to note that a block made BY THEM was in error.