Hot answers tagged simbl
That doesn't look like an extension, but a SIMBL Plugin. These can be found in the directiory /Library/Application Support/SIMBL/Plugins, and you should be able to remove the SafariOmnibar.bundle from there.
I doubt there's a SIMBL plugin to do that. What you're asking for would be a fairly extensive rewrite even if you had the source code for the Finder. Your best bets are what @jtbandes and @Richard's comments on your question state: get a Finder replacement that does that or use list view in the Finder.
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