Microsoft's new Edge browser, based on the Chromium project, is set to release on January 15, and when it does, it'll be missing a few features, such as history syncing and extension syncing. Another thing that'll be missing, for those using the current version of Edge, is the ability to set tabs aside to use later. But if you're using this feature in the current version of Edge.
As spotted by Techdows, if you install the stable version of Microsoft Edge - which is only available through unofficial methods - on Windows 10, your tabs set aside will be available as favorites. Upon launching the updated browser, when you right-click one of the tabs at the top of the screen, there'll be a menu item saying you can find your tabs set aside in Favorites. There, you can find them in a dedicated folder to tabs set aside, with each set of tabs grouped into a different folder. Since the new version of Edge will be added to Windows 10 as soon as it's generally available, displacing the current version, it makes sense for user content to be preserved somehow.
On the favorites page, you'll also see a message saying you can't currently set tabs aside in Edge. Microsoft has talked about the possibility of bringing some features over from the current version of Edge, and during a session at Build this year, no guarantee was given that the ability to set tabs aside would be among them. However, the text on this page could suggest it is happening at some point.
It's worth noting that the Canary and Dev channels of the new Edge have an interesting new feature called Collections, which can gather websites, images, and notes into user-created groups, which isn't too far off from how setting tabs aside worked. With the ability to add all the current tabs to a collection, for instance, the functionality would be nearly identical to how it works in the current version of the browser. It could end up being something completely different, though.