Bookmarklet that exports GPX files of trails and routes from Trailforks
In your web browser, create a new Bookmark called "Trailforks Export" and paste the contents of trailforks-export.bookmarklet into its URL field. For ease of use, save this bookmarklet in your Bookmarks Bar.
Go to Trailforks.com and find a route or trail page (example). Click the bookmark you created during Install. A GPX file containing a track of this route or trail should begin downloading.
This software is a quick stopgap for your own personal trail routing needs. Trailforks' built-in GPX downloads are substantially better quality (see Details below). If you find yourself using this bookmarklet frequently, you should invest in a Trailforks Pro membership.
Do not rely exclusively on GPX tracks generated by this software for navigation. They're a rough outline at best, and may omit dangerous features, lead you onto private property, indicate intersctions that don't exist, etc.
This software converts the polyline from a Trailforks map into a GPX file with the Mapbox JS implementation they employ on their page.
Polylines are a great way to deliver visual info in an extremely compact package, but they are not particularly data-rich. As an example, this multi-hour Mountain Bike loop contains about 1440 individual points when exported from a polyline using this software. My own GPS recording of a nearly indentical route has more than 13,000.
When logged-in as a Trailforks user, some pages that would normally display an interactve map will display a static image instead. You'll need to go to the specific Map page for a given trail/route to export. This software attempts to catch this gotcha and redirect you there via popup.