Stop Gnus word-wrapping (plain text) messages

[Sergey Organov]

Hello,

When I display a (plain text) message in Gnus by hitting <ENTER> at the
message in the Summary buffer, the display of the message content ends
up being word-wrapped at some (apparently fixed) column.

When I display the same message raw, by pressing <C-u g> in the Summary
buffer, long lines are just truncated, exactly as dictated by my generic
settings.

I want to disable this word-wrap (apparently performed by Gnus), but
can't figure how to achieve this. Please help!

Gnus v5.13

GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.5,
cairo version 1.16.0) of 2020-03-08, unofficial emacs-snapshot build:
http://emacs.ganneff.de/,
git commit 0a3f8da6e1a56ada409cf1677ac40fcc75a8a33c

-- 
Sergey Organov