What is the default Randomized Faiths & Rites game rule in CK3?

Off: Characters and Counties have historical Faiths and Rites. (patch 1.20.1.2)

Does changing the Randomized Faiths & Rites rule disable achievements?

Yes for “On”: the file gives it the flag blocks_achievements. The other settings keep achievements on.

Game rule · Game Modes · Faith

Randomized Faiths & Rites

Off · default
On ✕

Randomized Faiths & Rites is a game rule in Crusader Kings III (Game Modes and Faith) with 2 settings: Off (the default) and On. “On” disables achievements. Patch 1.20.1.2, from game/common/game_rules/00_game_rules.txt.

This section as JSON: /raw/game-rules.json

Quick answers (2)

What is the default Randomized Faiths & Rites game rule in CK3?: Off: Characters and Counties have historical Faiths and Rites. (patch 1.20.1.2)
Does changing the Randomized Faiths & Rites rule disable achievements?: Yes for “On”: the file gives it the flag blocks_achievements. The other settings keep achievements on.

2 settings

Off
Default
Characters and Counties have historical Faiths and Rites.
randomized_faiths_off
On
Disables achievements
Characters and Counties are assigned random Faiths, and a random Rite within that Faith. All Faiths in the game are available.
The script checks it once, in 1 place
On actions (the game's own hooks) 1
- on_game_start_after_lobby
Every has_game_rule = randomized_faiths_on in game/common and game/events, by the top-level object it sits in.
randomized_faiths_on

Source: game/common/game_rules/00_game_rules.txt line 1050 (key randomized_faiths), modifiers from game/common/modifiers, names from the English localisation; Crusader Kings III 1.20.1.2.