What does Holy Banner of Muhammad do in CK3?

Prestige +0.01/month (patch 1.20.0.3).

How do you get Holy Banner of Muhammad with the console?

effect create_artifact_pedestal_islamic_relic_effect_hist = { OWNER = root } — runs the scripted effect that makes it, for the character you play (debug mode).

What if the owner can't benefit from Holy Banner of Muhammad?

They get Court grandeur baseline +3 instead.

Court artifact · Large Wall Ornament

Holy Banner of Muhammad

IllustriousUniqueHoly relicThe Royal Court

Holy Banner of Muhammad is an illustrious large wall ornament artifact in Crusader Kings III: Prestige +0.01/month. Quality 100 and wealth 100; maximum durability 150. At game start it goes to a ruler the game picks — needs The Royal Court. It needs The Royal Court. Patch 1.20.0.3, from game/common/scripted_effects/01_exp1_historical_artifacts_creation_effect.txt.

Quick answers (3)

What does Holy Banner of Muhammad do in CK3?: Prestige +0.01/month (patch 1.20.0.3).
How do you get Holy Banner of Muhammad with the console?: effect create_artifact_pedestal_islamic_relic_effect_hist = { OWNER = root } — runs the scripted effect that makes it, for the character you play (debug mode).
What if the owner can't benefit from Holy Banner of Muhammad?: They get Court grandeur baseline +3 instead.

This is said to be the Holy Banner of Muhammad, a relic from the days of the prophet and a symbol of the entire Muslim faith.

Effects

Prestige+0.01/month

Also gets random bonuses when it is made, from add_scaled_artifact_modifier_piety_effect, add_scaled_artifact_modifier_grandeur_small_effect, add_scaled_artifact_modifier_devotion_effect — the bigger ones at higher rarity.

For an owner who can't benefit from it

The template gives these instead of the effects above when its “can benefit” check fails:

Court grandeur baseline+3

Who can benefit (can_benefit) (1 line of game script)

islamic_artifact_access_trigger = yes

As written in game/common/artifacts/templates (islam_artifact_template).

Counts as a holy relic for (is_holy_relic) (6 lines of game script)

OR = {
	religion = religion:islam_religion
	main_rite = {
		rite_has_parameter = islamic_syncretic_actor
	}
}

As written in game/common/artifacts/templates (islam_artifact_template).

History and who has it

Made before recorded history.
At game start: a ruler the game picks — needs The Royal Court.

How it is made

The game creates it with the scripted effect create_artifact_pedestal_islamic_relic_effect_hist. In the console (how to open it), this gives it to the character you play:

effect create_artifact_pedestal_islamic_relic_effect_hist = { OWNER = root }

Built from the effect's file; not run in the game by us.

Source: game/common/scripted_effects/01_exp1_historical_artifacts_creation_effect.txt, common/modifiers (artifact_placeholder_modifier), common/artifacts/templates (islam_artifact_template) and the English localisation, Crusader Kings III 1.20.0.3.