diff --git a/runtime/syntax/config.vim b/runtime/syntax/config.vim
index d13e89b394..2e8f62693c 100644
--- a/runtime/syntax/config.vim
+++ b/runtime/syntax/config.vim
@@ -6,6 +6,7 @@
 " 				(patch from Khym Chanur to add @Spell)
 " 				(patch from James McCoy to fix paren matching)
 " 				(2025 Sep 14 patch from Damien Lejay to detect unportable +=)
+" 				(2025 Sep 18 by Vim Project: fix inconsistent group name)
 
 " Well, I actually even do not know much about m4. This explains why there
 " is probably very much missing here, yet !
@@ -36,7 +37,7 @@ syn region  configmsg matchgroup=configfunction start="AC_MSG_[A-Z]*\ze(\[" matc
 syn region  configmsg matchgroup=configfunction start="AC_MSG_[A-Z]*\ze([^[]" matchgroup=configdelimiter end=")" contains=configdelimiter,@Spell
 
 " Help write portable shell code
-syn match acPlusEq '\v\+\=' containedin=ALLBUT,configcomment
+syn match configPlusEq '\v\+\=' containedin=ALLBUT,configcomment
 
 " Define the default highlighting.
 " Only when an item doesn't have highlighting yet
@@ -51,7 +52,7 @@ hi def link configkeyword   Keyword
 hi def link configspecial   Special
 hi def link configstring    String
 hi def link configmsg       String
-hi def link acPlusEq        Error
+hi def link configPlusEq    Error
 
 
 let b:current_syntax = "config"