If you opened Chrome recently and ModHeader was gone, or sitting there turned off, you're not alone. Microsoft pulled it from Edge Add-ons on July 3, 2026 and Google followed on July 10. Version 7.0.18 shipped a dormant collector for the domains you visit, plus install and update pings to a third-party server (The Hacker News has the details). The collector reportedly never switched on, but the listings are gone either way.
The annoying part: once Chrome turns an extension off, you can't open it, so the Export button is gone too. If you had a dozen profiles with tokens, URL filters and staging headers, that hurts.
Your profiles are still on your disk, though. Chrome keeps every extension's chrome.storage.local in a LevelDB folder under your browser profile, and ModHeader keeps everything under one key called profiles.
Where the folder is
ModHeader's id in the Chrome Web Store was idgpnmonknjnojddfkpgkljpfnnfcklj (on Edge Add-ons it was opgbiafapkbbnbnjcdomjaghbckfkglc).
Windows:
%LOCALAPPDATA%\Google\Chrome\User Data\Default\Local Extension Settings\idgpnmonknjnojddfkpgkljpfnnfcklj
macOS:
~/Library/Application Support/Google/Chrome/Default/Local Extension Settings/idgpnmonknjnojddfkpgkljpfnnfcklj
Linux:
~/.config/google-chrome/Default/Local Extension Settings/idgpnmonknjnojddfkpgkljpfnnfcklj
If you use several Chrome profiles, open chrome://version in the one where you had ModHeader and use its "Profile Path" instead of Default. If the folder isn't there, Chrome may have deleted it when it removed the extension, and then there's nothing left to recover. So do this soon, and don't click "Remove" on ModHeader before you have your profiles.
Option 1: a command line tool
Requestly published a small CLI that finds the folder and writes the same JSON file ModHeader's own export would have: npx @requestly/modheader-export-backup. You need Node 20 or newer. The file works with any tool that imports ModHeader JSON.
Option 2: read it in the browser
This is partly why I built Headerwise, a free and open source header editor. Its "Move from ModHeader" page lets you pick that folder and reads the LevelDB files right in the page (I wrote a small LevelDB and snappy reader in TypeScript for it), with nothing uploaded. Headers, URL filters, site, type and method filters, URL replacements and cookie rules come over, and the profile you had selected stays on. Chrome Web Store, source.
Option 3: by hand
If you'd rather not run anything: copy the folder somewhere safe first, then open the copy with any LevelDB viewer and read the value of the profiles key. It's plain JSON.
Whatever you pick
Exports often hold Authorization tokens and session cookies. Treat the file like a password: don't commit it, and rotate anything sensitive you kept in ModHeader if you're not sure what happened to it.
If you used ModHeader in Selenium or Playwright tests, that broke separately: its test package ships a Manifest V2 build that current Chrome won't load. Here's what works now. And if your setup needs something none of these handle, tell me in the comments.
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