set_pilgrimage_distance_variable_effect

set_pilgrimage_distance_variable_effect = {
	# Requires PILGRIM = character
	# Requires HOLY_SITE = barony_title
	$PILGRIM$.capital_barony = { # Only landed characters can go on regular pilgrimages
		save_temporary_scope_as = start_barony
	}
	# Calculate distance to the target holy site
	# The value set indicates how many Journey Events a character will get
	if = {
		limit = {
			scope:start_barony = {
				squared_distance = {
					target = $HOLY_SITE$
					value > long_pilgrimage_max_length
				}
			}
		}
		scope:activity = {
			set_variable = {
				name = pilgrimage_distance
				value = flag:very_long_pilgrimage_var
			}
		}
	}
	else_if = {
		limit = {
			scope:start_barony = {
				squared_distance = {
					target = $HOLY_SITE$
					value > medium_pilgrimage_max_length
				}
			}
		}
		scope:activity = {
			set_variable = {
				name = pilgrimage_distance
				value = flag:long_pilgrimage_var
			}
		}
	}
	else_if = {
		limit = {
			scope:start_barony = {
				squared_distance = {
					target = $HOLY_SITE$
					value > short_pilgrimage_max_length
				}
			}
		}
		scope:activity = {
			set_variable = {
				name = pilgrimage_distance
				value = flag:medium_pilgrimage_var
			}
		}
	}
	else = {
		scope:activity = {
			set_variable = {
				name = pilgrimage_distance
				value = flag:short_pilgrimage_var
			}
		}
	}
}

As written in game/common/scripted_effects/00_pilgrimage_effects.txt.