Game concept
Inventory Artifact
The game also links it as Inventory Artifacts.
From the game's encyclopedia
Inventory Artifacts are Artifacts that a Character wears or carries with them, such as a weapon or a crown.
There is no limit to how many Artifacts a Character can have, but only those equipped in a slot of its type has any effect.
You can create new Inventory Artifacts from Inspired Characters, or from the Commission Artifact Decision.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Inventory Artifact is an entry of Crusader Kings III's in-game encyclopedia. The game explains it: "Inventory Artifacts are Artifacts that a Character wears or carries with them, such as a weapon or a crown." It is part of Artifact. The game also links it as Inventory Artifacts. Patch 1.20.1.2, from game/common/game_concepts/00_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/00_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.