_locations.conf missing jinja2 variables?

[Oratorian]

I ran into a wierd problem with custom location.

my webapp runs its own location like /login
so for npm to forward that corretly you need to set location to /help/ and proxy_pass ip:port/; trailing slash is important

then i stumbled upton the templates folder and _locations.conf uses proxy_pass {{ forward_scheme }}://{{ forward_host }}:{{ forward_port }}{{ forward_path }};

but {{ forward_path }} is nerver set anywhere so the final proxy_pass in nginxs .conf always ends in
proxy_pass http(s)://ip:port; and missing the trailing slash.