There hasn't been any official announcement at Microsoft Build 2019 yet but it looks like you can download the Dev and Canary builds for Edge on Mac now! See their following hosted links:
- Dev: https://officecdn.microsoft.com/pr/C1297A47-86C4-4C1F-97FA-950631F94777/MacAutoupdate/MicrosoftEdgeDev-220.127.116.11.pkg
- Canary: https://officecdn.microsoft.com/pr/C1297A47-86C4-4C1F-97FA-950631F94777/MacAutoupdate/MicrosoftEdgeCanary-18.104.22.168.pkg
TIP: If you want to enable dark mode on the browser, make sure it's enabled for the OS then enter
edge://flags in the URL bar and switch "Microsoft Edge theme" to "Enabled".