How do I find out which file or plugin last set a particular Vim option?

Explanation

:verbose set {option}? shows the current value of an option and reports exactly which file set it last — the full path and line number. This is the definitive debugging tool when an option behaves unexpectedly and you cannot find where it is being changed.

How it works

• :set {option}? prints the current value of {option} (the ? suffix queries without changing)
• :verbose prefix adds provenance information: the file path and line number of the last set call
• Works for any option: boolean, string, or number
• :verbose setlocal {option}? checks the buffer-local value
• :verbose setglobal {option}? checks the global value

Example

Your tabstop seems wrong in some files. Run:

:verbose set tabstop?

Output:

tabstop=2
      Last set from ~/.vim/ftplugin/javascript.vim line 3

Now you know exactly which file is overriding your vimrc setting.

Tips

• Use :verbose map {key} to find where a key mapping was defined — same provenance approach for mappings
• :verbose autocmd {event} lists all autocmds for an event with their source files
• For a full diagnostic overview, :scriptnames lists every script file loaded in the current session in load order
• :set all displays the current value of every option at once — useful for a broad audit before targeting :verbose set