This is a Just-in-Time (JIT) access request web app. It's like
https://github.com/tailscale/accessbot but without the Slack bit and
instead being a webserver.
It's a tsnet webserver, so it
knows who you are already and which device you want access for.
It gets its secrets from setec, or from
local files. Optionally, it uses workload
identity to
authenticate to the Tailscale API.
The hallpass server is a tsnet web application
that allows users to use request instantaneous, time-bound access, known as
just-in-time access, to Tailscale resources from other people in their
organization
It is effectively the web-based version of github.com/tailscale/accessbot.