26.1.2 - 1.3.0

Added client.config.RuleFormat — how a config line maps to the fields of a RuleType. RuleFormat.PIPE is the previous positional format; mods can now edit other syntaxes (prefixes, key=value pairs, lines saved in an older layout) and provide their own cross-field checks and row summaries.
Added the field kinds BLOCK, CUSTOM (a picker whose options the mod provides by Field.source()), CHOICE and TOGGLE (buttons instead of text inputs).
Added client.config.RegistrySuggestionSource — a RuleSuggestionSource backed by RegistryCandidates, which mods extend for their CUSTOM fields.
RuleListScreen can take an EntryPicker to add several entries at once next to the Add button.
RuleListScreen.withDefaults adds a Reset button.
RuleSuggestionSource.Option can have an icon, shown in the suggestion list.
RuleEditScreen rows now shrink on short screens so rules with many fields stay above the error line and buttons.
Long explanations under the screen titles are cut off with the full text on hover instead of running off the screen.
Fixed a crash in RuleType.validate when a min/max field pair was optional and left empty, and ATTRIBUTE_VALUE fields assuming the attribute is the line's second field.

RuleSuggestionSource now takes the RuleType.Field (and the line's current values where they matter) instead of a Kind and a context string.

26.1.2 - 1.2.1

Added ConfigHelper.getOrDefault/ConfigHolder.getOrDefault — a guard that returns a fallback instead of throwing IllegalStateException when a config value is read before its spec is loaded (e.g. datagen or other contexts where no config file is ever loaded, such as a block's isEnabled(FeatureFlagSet) check running under the loot table provider).

Added util.ModCompat.isLoaded(String modId) — a one-line check for whether another mod is loaded, replacing hand-rolled per-mod loader enums.
Added util.RomanNumeralUtil.generate(int) — converts an int to a Roman numeral string.

Added client.util.PoseStackHelper.translateAndScale/rotateItem — common PoseStack transforms for drawing an ItemStack at an offset inside a block entity renderer.
Added client.util.RenderingUtils.swing/flap/bob/walk — limb-animation math for ModelParts.

Added client.config.RegistryCandidates — turns a built-in or datapack registry (entities, items, blocks, attributes, enchantments, biomes) into a searchable candidate list for EntryPickerScreen, including a fallback for datapack-driven registries (biomes, enchantments) when no world is loaded, e.g. editing config from the title screen.
Added a second, heavier config-list editor for pipe-delimited, multi-field config rows: client.config.RuleType (field schema with per-field validation), RuleSuggestionSource (caller-supplied id lookups), RuleListContext (translation key prefixes), RuleListScreen and RuleEditScreen. This complements the existing append-only PickerListScreen for config lists that need several validated fields per row, edited in place.