unset bash variable not working as expected

Describe the bug I thought you could include unset commands in a direnv config and it would clear variables if they exist. https://direnv.net/man/direnv.1.html#usage I'm seeing errors that stop direnv from continuing when I put an unset line in a .env config file. The export lines will work as expected if I don't include the unset ones.

To Reproduce

$ mkdir ~/scratch/direnvtest

$ echo 'unset FOO'>~/scratch/direnvtest/.env

$ cd ~/scratch/direnvtest
direnv: error /Users/blake/scratch/direnvtest/.env is blocked. Run `direnv allow` to approve its content

$ direnv allow
direnv: error invalid line: unset FOO
direnv: export ~XPC_SERVICE_NAME

Expected behavior When a line of unset FOO exist in the .env file direnv will unset the variable if it exists. In my test case FOO does not exist.

Environment

• OS: macOS 14.6.1 23G93 arm64
• Shell: GNU bash, version 5.2.26(1)-release (aarch64-apple-darwin23.2.0)
• Direnv version 2.34.0 & 2.33.0

Additional context Hopefully, I'm not missing something basic here...