diff --git a/docs/usage/configuration-options.md b/docs/usage/configuration-options.md
index 29fefd3250a6f5e463b24fba9403f28276f5364f..58d658bf12ee8d3d89e4e091e2b09522bd6e84a6 100644
--- a/docs/usage/configuration-options.md
+++ b/docs/usage/configuration-options.md
@@ -2219,7 +2219,7 @@ Use the syntax `!/ /` like this:
 
 ### matchFileNames
 
-Renovate will compare `matchFileNames` glob matching against the dependency's package file or lock file.
+Renovate will compare `matchFileNames` glob matching against the dependency's package file and also lock file if one exists.
 
 The following example matches `package.json` but _not_ `package/frontend/package.json`:
 
@@ -2262,6 +2262,8 @@ The following example matches any file in directories starting with `app/`:
 }
 ```
 
+It is recommended that you avoid using "negative" globs, like `**/!(package.json)`, because such patterns might still return true if they match against the lock file name (e.g. `package-lock.json`).
+
 ### matchDepNames
 
 ### matchDepPatterns