How do I set environment variable values in developer runtime?

[bellds]

Background I asked this question via Stackoverflow and cross posting because the base README.md says to post questions here.

Question Codewind has the notation of a Linked Project that lets a person define an environment variable which will hold the host name of the deployed Linked Project.

However, how does a person define and set other environment variables that get will be visible in the local developer Docker runtime deployment? For example, environment variables to hold the user name or password for an external resource like a database.