When trying to install jabba for PowerShell neither the bash nor the PowerShell method works. The bash method installs it, however running jabba in pwsh gives the "command not found" error. Using the PowerShell script that is intended for Windows, you get the following error:

Installing v0.11.2...
/Users/marcel/.jabba\bin\jabba does not appear to be a valid binary.
Check your Internet connection / proxy settings and try again.
if the problem persists - please create a ticket at https://github.com/shyiko/jabba/issues.

Possible solution: Check if running on Windows, then run the exe, otherwise run the non exe file. If it's fine I can create a PR for this.