exit arc · take your Arc sidebar with you

How to run it

Install it with Homebrew:

brew install meelijane/tap/exit-arc

Then run it in Terminal:

exit-arc

Without Homebrew: download exit-arc.pyz from the latest release and run python3 exit-arc.pyz.

It asks a few questions, then does the rest:

Which Arc profile?

Only asked if you have more than one. The default is all of them.
Here's what it found

Your Favourites, and each space with its pinned tabs and folders.
Where are you moving to?

Firefox, Zen, Chrome, or no browser: just save the files.
What should it set up there?

It lists only what that browser supports. Press Enter for all of them, or type the numbers you want.
Keep your bookmarks or replace them?

Only asked if the browser already has bookmarks of yours. The default is to keep them and import the bookmarks file yourself; it shows you how.
Where should the files go?

The default is ~/Desktop/arc-export.
Go ahead?

Nothing changes until you say yes. If the browser is open, it asks before quitting it.

macOS with Arc's data still on disk (~/Library/Application Support/Arc)
Python 3.8 or newer. Macs with Homebrew already have it; otherwise macOS offers to install it the first time you run python3.
The browser you're moving into, if any. Open it once and quit it first, so it has a profile.

arc-sidebar.md: a readable page with a heading per space, nested folders, Favourites and your extensions
arc-tabs.csv: one row per tab
arc-bookmarks.html: a standard bookmarks file any browser can import
arc-export.json: everything, for other tools

Step	Firefox	Zen	Chrome	Just the files
BookmarksFavourites + a folder per space	Yes, on the toolbar (replaces existing bookmarks; asks first)	Yes, same as Firefox	Experimental: added to the bookmarks bar, yours kept	HTML, CSV, Markdown, JSON
Spaces	No: you get a toolbar folder per space	Yes: real Zen spaces with your pinned tabs and folders	No: Chrome has no spaces	Listed in every format
Favourites	Real pinned tabs	Zen Essentials	No	Listed in every format
Vertical tabs	Yes	Built in	No	Not applicable
New tab cleanupNo sponsored shortcuts or widgets	Yes	Yes	No	Not applicable
Extensions	Finds official add-ons; you approve each	Same as Firefox	Opens each Web Store page; you click Add	Listed in Markdown and JSON

Adding bookmarks to Firefox or Zen replaces every bookmark in the profile. If you already have bookmarks there, exit-arc asks first and keeps them unless you choose to replace them.
Everything it changes in the browser is backed up first, next to your files.
Chrome bookmarks are experimental. If they don't appear, import arc-bookmarks.html in Chrome by hand.
Zen spaces are tested on Zen 1.24. Zen doesn't document the file they live in, so a future Zen version may change the format.
Extensions: only extension names are sent to addons.mozilla.org, and only when you choose Extensions. Nothing is installed without your OK.

For history and passwords, use the browser's own importer or a password manager.