What it can trim
Konformista is camera-format aware. It trims ProRes, long-GOP H.264/265, MXF (ARRIRAW and Sony X-OCN included), RED (.r3d, on macOS and Windows), Blackmagic (.braw), Canon Cinema RAW Light (.crm), image sequences (DPX, EXR, and ARRIRAW .ari and .arx frames), and WAV/BWF audio. Stills, graphics, and anything it can't safely trim ship whole, so nothing is silently altered.
Handles
Handles run from none to 48 frames on each side; 12 is a sensible default. More handles mean more room for transition changes and retimes at the far end, at the cost of package size.
On the other side
The colorist opens the package with the free Konformer app. It reconstructs the trimmed clips as ordinary media files next to the package before the timeline imports, so everything relinks cleanly: in Resolve they behave like any other online clips, cross-platform.
When to leave it off
Skip trimming when the colorist is on the same storage and already has the originals, or when the far end needs whole camera files, to re-edit rather than just grade.
The Export window: trimmed media and handles.
For what survives the timeline conform itself, see the roundtrip comparison. For the rest of the handoff, see the docs.