Change User Agent

how can i change user agent in tt-rss and where can i set it?
ps for docker install

Docker:

$ grep 'http user agent' .env
TTRSS_HTTP_USER_AGENT=http user agent

Rebuild docker container.

Afterwards:

$ grep fake /var/log/nginx/*myhost*                                                 
/var/log/nginx/access.myhost.co.uk.log:172.18.0.3 - - [15/Mar/2022:14:04:32 +0000] "GET /fake.rss HTTP/2.0" 404 107 "-" "http user agent"

Many thanks! all works