Hai ragione; è un filtro avanzato e un’alternativa valida! Dovresti comunque codificare il parametro; quello era il tuo problema (e potrebbe diventarne un altro, a seconda di cosa usi).
Ecco un elenco di filtri avanzati principali:
in:bookmarks
in:created
in:mine
in:likes
in:watching
in:tracking
in:all-pms
in:first
in:personal-direct
in:pinned
in:posted
in:seen
in:tagged
in:unseen
in:untagged
in:wiki
with:images
status:archived
status:closed
status:noreplies
status:open
status:public
status:single_user
max_posts:<number>
max_views:<number>
min_post_count:<number>
min_posts:<number>
min_views:<number>
posts_count:<number>
after:<date>
badge:<name|id>
before:<date>
category:<slug|id>
created:@<username>
filetypes:<ext[,ext,..]>
filetype:<ext[,ext,..]>
group_messages: <name|id>
group: <name|id>
tag:<name>
tags:<name,name>
-tag:<name>
-tags:<name,name>
user:<username|id>
#<[=]category_slug[:subcategory_slug]>
@<username>