Unresolved

What is known to exist but not decoded, or decoded only partly. Contributions with evidence (an export before and after one UI change) are welcome.

Not decoded

Item	What is known
Track automation	fader and plugin automation lanes of tracks are not read
Keyframe flags	every keyframe made in the UI stores 0x000C0000; probably the interpolation type. compose writes the same value
Track-level Dialogue Leveler	not settable through the API; the track record carries no UI_… parameters until set in the UI
Plugin bypass	where an insert plugin's bypass is stored is not known
Plugin state flags	decoded only for track built-in Voice Isolation (bit 0x10). Insert plugins (2 has been seen) and the other built-in FX: raw with --all
Bus solo, bus pan	items exist in the first part of the bus table but are not verified
0x0B9	non-zero on exactly one track per timeline (1, 2 = channel within that track). It is not the track selection (0x0AA). Printed raw as unknown_0b9
0x13B	meaning unknown; printed raw as unknown_13b
0x008 / 0x009	possibly pan related (writing −200 changed the level by about +1.5 dB)
0x11B non-zero values	0 = expander; any non-zero value shows the gate. The meaning of the individual values is not known
EQ knob 0x333+k	follows the frequency; probably the knob position; not used
Fade curve shape	the curve passes through the stored point; for a point at 50 % it is the straight fade's dB curve times a constant. For other positions the shape between the ends and the point is not modelled
Media Clip fields 15, 16	kept as they are

Partly calibrated

Item	State
Expander threshold 0x116	÷10 dB from a single point (assumed)
Expander ratio 0x253	all 14 measured points are in the table; no independent check
Limiter plugin release	one value (0.8829 = 190.55 ms)
De-Esser reaction	one value (0.5 = medium)
EQ Q	fitted on 0.8–5.0; the ends of the UI range (0.3, 10.3) not checked
Dynamics hold / release	knob position 100–250 can be off by more than ±1 %

Solved (kept for reference)

• Fade curve: params 99 / 100, a big-endian (position %, level in 0.1 dB) point. See Fade curves.
• Track Voice Isolation on/off: bit 0x10 of the plugin record's state flags. See Plugins.
• EQ bands: see Conversions. The old eq_band1_type → 0x0DE mapping was wrong (that item is the processing order) and has been removed.

Not supported by compose

Refused rather than guessed: overlapping clips, transitions other than a centered Cross Fade 0 dB, curved fades, several audio streams per file, the same media on several tracks, seconds or sub-frame positions, non-default channel mappings when the channel count changes, media other than the supported formats, and items other than audio clips and transitions on the template's audio tracks.

Also note: FCPXML fadeIn / fadeOut are ignored by Resolve on import, so fades cannot be brought in that way.