diff --git a/runtime/doc/terminal.txt b/runtime/doc/terminal.txt
index 68528d3..3869bcd 100644
--- a/runtime/doc/terminal.txt
+++ b/runtime/doc/terminal.txt
@@ -1588,9 +1588,9 @@
 
 Change default signs ~
 							*termdebug_signs*
-Termdebug uses the last two characters of the breakpoint ID in the
-signcolumn to represent breakpoints. For example, breakpoint ID 133
-will be displayed as `33`.
+Termdebug uses the hex number of the breakpoint ID in the signcolumn to
+represent breakpoints. if it is greater than "0xFF", then it will be displayed
+as "F+", due to we really only have two screen cells for the sign.
 
 If you want to customize the breakpoint signs: >
 	let g:termdebug_config['sign'] = '>>'