(Context: Win 10 on all 3 systems)
There's a folder I access almost daily, and I used to keep it in my Dropbox synced folder. A while back I was reorganizing and decided to move it to my OneDrive folder. To save time when I forgot that I moved it, I placed a folder shortcut to the new location where the folder used to be in Dropbox.
Today I added an SSD to my desktop system, started with a fresh install of Win 10, formatted the old HDD and added it as a second drive. Since the OneDrive sync location is different after the changes, I figured I should go update the shortcut. To my surprise it already had the correct path to the new drive.
When I created the shortcut I told myself that I'd only be able to use it on my desktop system and it'd just serve as a reminder when I was working on my laptop (my user folder was named differently which meant the OneDrive sync path was different on the two systems). However, I just checked on my laptop and the copy of the shortcut on that system has the correct path for that system, and I realized I've probably been using it on my laptop without thinking about it.
The modified date on both systems is the same (back in February). Both shortcuts are showing the full letter-drive path with no system variables.
What black magic is this? Is it Dropbox, OneDrive, or Windows 10 that detected the need and made it happen, and how is it working?