HTTP304 on static files
nginx_1 | 82.253.82.112 - - [28/Feb/2019:12:12:30 +0000] "GET /static/css/escriptorium.css HTTP/1.1" 304 0 "http://ns342141.ip-5-196-76.eu/document/4/images/" "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:65.0) Gecko/20100101 Firefox/65.0" "-"
tells the client to use the cached file even though it has changed on disk.