Gee, I feel like an idiot. Almost everything is explained over at file changes.txt. I'll just post the relevant text for reference here.
Auxiliary file changes for 0.34.01:
interactions
interaction_standard.txt has some basic processes
the examples are in "raw/interaction examples"
creatures
ability to do the interactions, using [CAN_DO_INTERACTION:<token>] -- this includes cleaning, ink spray, and physical social stuff
[CAN_DO_INTERACTION:MATERIAL_EMISSION] taken from fire imp, MATERIAL_EMISSION is defined in interaction_standard.txt
[CDI:ADV_NAME:Hurl fireball]
[CDI:USAGE_HINT:ATTACK]
[CDI:BP_REQUIRED:BY_CATEGORY:HAND]
[CDI:FLOW:FIREBALL]
[CDI:TARGET:C:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:C:15]
[CDI:MAX_TARGET_NUMBER:C:1]
[CDI:WAIT_PERIOD:30]
[CAN_DO_INTERACTION:MATERIAL_EMISSION_WITH_HIDE_EFFECT] taken from squid
[CDI:ADV_NAME:Squirt ink]
[CDI:USAGE_HINT:FLEEING]
[CDI:LOCATION_HINT:IN_WATER]
[CDI:BP_REQUIRED:BY_TYPE:UPPERBODY]
[CDI:MATERIAL:LOCAL_CREATURE_MAT:INK:SPATTER_LIQUID] <-- SPATTER_LIQUID is a new "breath" attack, SPATTER_POWDER too
[CDI:VERB:squirt ink:squirts ink:NA]
[CDI:TARGET:C:SELF_ONLY] <-- this is basically book-keeping for the two effects in the interaction
[CDI:TARGET:D:SELF_ONLY]
[CDI:WAIT_PERIOD:200]
[CDI:FREE_ACTION] <-- they can spray ink and also move away
[CAN_DO_INTERACTION:CLEANING] taken from cat
[CDI:ADV_NAME:Clean]
[CDI:USAGE_HINT:CLEAN_SELF]
[CDI:USAGE_HINT:CLEAN_FRIEND]
[CDI:BP_REQUIRED:BY_CATEGORY:TONGUE]
[CDI:VERB:lick:licks:lick each other]
[CDI:CAN_BE_MUTUAL] <-- not yet implemented
[CDI:TARGET:A:SELF_ALLOWED:TOUCHABLE] <-- so the animal can lick themselves or anybody nearby
[CDI:TARGET_RANGE:A:1]
[CDI:MAX_TARGET_NUMBER:A:1]
[CDI:WAIT_PERIOD:10]
[CAN_DO_INTERACTION:BP_BUMP] taken from cat
[CDI:ADV_NAME:Head bump]
[CDI:USAGE_HINT:GREETING]
[CDI:BP_REQUIRED:BY_CATEGORY:HEAD]
[CDI:VERB:head-bump:head-bumps:bump heads]
[CDI:CAN_BE_MUTUAL] <-- not yet implemented
[CDI:TARGET:A:SELF_ONLY]
[CDI:TARGET:B:TOUCHABLE]
[CDI:TARGET_RANGE:B:1]
[CDI:MAX_TARGET_NUMBER:B:1]
[CDI:WAIT_PERIOD:20]
they can retract into bodyparts/roll into balls using RETRACT_INTO_BP
[RETRACT_INTO_BP:BY_CATEGORY:BODY_UPPER:roll into a ball:rolls into a ball:unroll:unrolls]
they will retract when they are frightened and near to an enemy
attacks while retracted will be much more likely to hit the retract part
they can root around and stir up vermin using ROOT_AROUND
[ROOT_AROUND:BY_CATEGORY:BILL:root around in:roots around in]
they can be made to eat vermin using GOBBLE_VERMIN_CREATURE and GOBBLE_VERMIN_CLASS
[GOBBLE_VERMIN_CREATURE:<creature>:<caste>] where <caste> can be ALL
[GOBBLE_VERMIN_CLASS:<class>] where class is a CREATURE_CLASS like the new EDIBLE_GROUND_BUG
they can drop extra objects during butchery with EXTRA_BUTCHER_OBJECT
[EXTRA_BUTCHER_OBJECT:BY_CATEGORY:GIZZARD]
[EBO_ITEM:SMALLGEM:NONE:ANY_HARD_STONE] <-- ANY_HARD_STONE is special, but you can use the standard material token list too
[EBO_SHAPE:GIZZARD_STONE] <-- this is a shape for a gem from descriptor_shape_standard.txt
DIVE_HUNTS_VERMIN is a new vermin hunting behavior, although it is limited for fortress pets because of the known flier troubles there
removed werewolf and whale and some redundant animal people from the old files
a ton of new sponsorship creatures -- the eight that got new tags are in the old files, the 112 that didn't get their own tags are in probationary new files, although I don't promise to give every one of them a special tag over time
NOT_LIVING replaces CANNOT_UNDEAD
material force multiplier, general material force multiplier
syndromes
SYN_INGESTED will work now
there are new tags here -- see the interaction examples in "raw/interaction examples" for syntax, here are some examples:
CE_ADD_TAG -- It's a pretty zombie-centric list (basically whatever came up for us). Support for other creature tags will be added.
EXTRAVISION
OPPOSED_TO_LIFE
SUPERNATURAL
NOT_LIVING
NOEXERT
CRAZED
BLOODSUCKER
NOPAIN
NOBREATHE
HAS_BLOOD
NOSTUN
NONAUSEA
NO_DIZZINESS
NO_FEVERS
TRANCES
NOEMOTION
LIKESFIGHTING
PARALYZEIMMUNE
NOFEAR
NO_EAT
NO_DRINK
NO_SLEEP
MISCHIEVOUS
NO_PHYS_ATT_GAIN
NO_PHYS_ATT_RUST
NOTHOUGHT
NO_THOUGHT_CENTER_FOR_MOVEMENT
NO_CONNECTIONS_FOR_MOVEMENT
CAN_SPEAK
CAN_LEARN
UTTERANCES
MORTAL
NO_AGING
STERILE
FIT_FOR_ANIMATION
FIT_FOR_RESURRECTION
CE_REMOVE_TAG
CE_DISPLAY_TILE
CE_DISPLAY_NAME
CE_FLASH_TILE
CE_PHYS_ATT_CHANGE
CE_MENT_ATT_CHANGE
CE_BODY_APPEARANCE_MODIFIER
CE_BP_APPEARANCE_MODIFIER
CE_MATERIAL_FORCE_MULTIPLIER
CE_SPEED_CHANGE
CE_BODY_MAT_INTERACTION -- only works on hist figs, causes that hist figs body material to cause interaction as a syndrome mat.
CE_CAN_DO_INTERACTION
CE_BODY_TRANSFORMATION
CE_SKILL_ROLL_ADJUST
xml
the legends xml has a lot of new info for historical figures
entities
PLAINS gets BUILDS_OUTDOOR_TOMBS
PLAINS gets all the trap comps
world gen params
some have been replaced, here are the new ones (might be missing some):
NIGHT_TROLL_NUMBER -- all of the following control how many random definitions are created, if set to zero that world won't have any
BOGEYMAN_NUMBER
VAMPIRE_NUMBER
WEREBEAST_NUMBER
SECRET_NUMBER
REGIONAL_INTERACTION_NUMBER
DISTURBANCE_INTERACTION_NUMBER
EVIL_CLOUD_NUMBER
EVIL_RAIN_NUMBER
graphics
SKELETON/ZOMBIE -> ANIMATED
announcements
there are some new ones, mostly or all at the bottom of the file
reactions
you can make BOOK items in reactions, and add PAGES improvements to them
pages are always blank though
new keys (this might not be it, but it wasn't many)
A_ACTION_ABILITY:A
A_ACTION_POWER:P
changed keys
A_BARTER_CURRENCY_2 -> O
removed keys
A_BARTER_CURRENCY_3 to 9