patch 8.2.3743: ":sign" can add a highlight group without a name Commit: https://github.com/vim/vim/commit/5e18ccc60bdddc4aa39ab039f1a7c918f29e67ce Author: Bram Moolenaar <Bram@vim.org> Date: Sun Dec 5 13:02:50 2021 +0000 patch 8.2.3743: ":sign" can add a highlight group without a name Problem: ":sign" can add a highlight group without a name. Solution: Give an error if the group name is missing. (closes https://github.com/vim/vim/issues/9280)

|i+0&#ffffff0|n|t| |c|a|t|;| @66
|i|n|t| >d+0&#ffff4012|o|g|;+0&#ffffff0| @66
|c|a|t| |=| |d+0&#ffff4012|o|g|;+0&#ffffff0| @64
|~+0#4040ff13&| @73
|~| @73
|~| @73
|~| @73
|~| @73
|~| @73
|/+0#0000000&|d|o|g| @35|[|1|/|2|]| @11|2|,|5| @10|A|l@1|