Signets
A Guild Wars skill family whose in-fiction origin is Orrian text — the setting Guild Wars 3 occupies.
Signets are a long-running Guild Wars skill type. Their franchise lore traces them to Orrian texts, which connects a mechanic players have used since 2005 directly to Guild Wars 3's setting.
What that means for the new game is unstated. It is recorded here because the link is in the existing lore, not because ArenaNet has drawn it.
Related
Orr
Guild Wars 3's setting: the human kingdom of Orr, standing, centuries before the Cataclysm that drowned it.
The Six Gods
The human pantheon — and, in Guild Wars 3's era, present in the world rather than remembered.