What is the default Exclave Independence game rule in CK3?

Significant (AI Only): Exclaves of Independent AI Rulers at peace will be removed on succession unless connected via a naval path or part of the De Jure territory. (patch 1.20.1.2)

Does changing the Exclave Independence rule disable achievements?

No: none of its 7 settings carries the flag blocks_achievements in patch 1.20.1.2.

Game rule · Titles & Realm · Tweaks

Exclave Independence

Off
Limited (AI Only)
Significant (AI Only) · default
Total (AI Only)
Limited
Significant
Total

Exclave Independence is a game rule in Crusader Kings III (Titles & Realm and Tweaks) with 7 settings: Off, Limited (AI Only), Significant (AI Only) (the default), Total (AI Only), Limited, Significant and Total. None of its settings 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 Exclave Independence game rule in CK3?: Significant (AI Only): Exclaves of Independent AI Rulers at peace will be removed on succession unless connected via a naval path or part of the De Jure territory. (patch 1.20.1.2)
Does changing the Exclave Independence rule disable achievements?: No: none of its 7 settings carries the flag blocks_achievements in patch 1.20.1.2.

7 settings

Off
Independent Rulers can have exclaves (disconnected land) anywhere in the world.
The script checks it 2 times, in 2 places
Events 2
- game_rule.2
- game_rule.3
Every has_game_rule = off_exclave_independence in game/common and game/events, by the top-level object it sits in.
off_exclave_independence
Limited (AI Only)
Exclaves of Independent AI Rulers at peace will be removed on succession unless connected to the Capital area by one County, via a naval path or part of the De Jure territory.
The script checks it once, in 1 place
Scripted effects 1
- game_rule_exclave_independence_effect
Every has_game_rule = ai_limited_exclave_independence in game/common and game/events, by the top-level object it sits in.
ai_limited_exclave_independence
Significant (AI Only)
Default
Exclaves of Independent AI Rulers at peace will be removed on succession unless connected via a naval path or part of the De Jure territory.
The script checks it once, in 1 place
Scripted effects 1
- game_rule_exclave_independence_effect
Every has_game_rule = ai_significant_exclave_independence in game/common and game/events, by the top-level object it sits in.
ai_significant_exclave_independence
Total (AI Only)
Exclaves of Independent AI Rulers at peace will be removed on succession unless they are connected via a naval path.
The script checks it once, in 1 place
Scripted effects 1
- game_rule_exclave_independence_effect
Every has_game_rule = ai_total_exclave_independence in game/common and game/events, by the top-level object it sits in.
ai_total_exclave_independence
Limited
Exclaves of Independent Rulers at peace will be removed on succession unless connected to the Capital area by one County, via a naval path or part of the De Jure territory.
The script checks it once, in 1 place
Scripted effects 1
- game_rule_exclave_independence_effect
Every has_game_rule = limited_exclave_independence in game/common and game/events, by the top-level object it sits in.
limited_exclave_independence
Significant
Exclaves of Independent Rulers at peace will be removed on succession unless connected via a naval path or part of the De Jure territory.
The script checks it once, in 1 place
Scripted effects 1
- game_rule_exclave_independence_effect
Every has_game_rule = significant_exclave_independence in game/common and game/events, by the top-level object it sits in.
significant_exclave_independence
Total
Exclaves of Independent Rulers at peace will be removed on succession unless they are connected via a naval path.
The script checks it once, in 1 place
Scripted effects 1
- game_rule_exclave_independence_effect
Every has_game_rule = total_exclave_independence in game/common and game/events, by the top-level object it sits in.
total_exclave_independence

Source: game/common/game_rules/00_game_rules.txt line 406 (key exclave_independence), modifiers from game/common/modifiers, names from the English localisation; Crusader Kings III 1.20.1.2.