Getting the lastest Edge and the latest MSEdgeDriver
We have these files that list the latest WebDriver binary version of each Edge channel that you can download from that site:
https://msedgedriver.azureedge.net/LATEST_BETA
https://msedgedriver.azureedge.net/LATEST_CANARY
https://msedgedriver.azureedge.net/LATEST_STABLE
https://msedgedriver.azureedge.net/LATEST_DEV
For WebPlatformTests, we use this script to download and install Edge: https://github.com/web-platform-tests/wpt/blob/master/tools/ci/azure/install_edge.yml
And then use this to download Edge driver: https://github.com/web-platform-tests/wpt/blob/4398d74fea97068f29499dcd1c6d6d6b268b9940/tools/wpt/browser.py (line 1016).