add build-time variable list

README.md

@@ -68,11 +68,17 @@ Note: `docker compose` without the hyphen is now the primary method of using doc
 
 ### Build-time variables
 
-placeholder
+These variables must be provided at the time of the docker build, and can be provided by updating the .env file. Changing these is not required for evaluation, but may be required for running in producion.
+
+* BASE_URL
+* NEXT_PUBLIC_APP_URL
+* NEXT_PUBLIC_LICENSE_CONSENT
+* NEXT_PUBLIC_TELEMETRY_KEY
 
 ### Run-time variables
 
 placeholder
+
 ## Git Submodules
 
 This repository uses a git submodule.