URML (substrate-neutral robot intent language) — RFC requesting feedback on ORB-SLAM3 visual-SLAM cross-citation

[idoco2003]

Hi UZ-SLAMLab / ORB-SLAM3 team,

URML (urml.dev) is a small, opinionated, human-readable language for describing robot intent — Apache-2.0, substrate-neutral by design. URML's perception manifest needs to declare a visual-SLAM substrate; ORB-SLAM3 is the canonical reference. Engagement is cross-citation only at the API boundary — GPL-3.0 prevents URML's Apache-2.0 adapter from embedding ORB-SLAM3 source, but URML's manifest can declare ORB-SLAM3 cleanly as the visual-SLAM substrate.

This is a proposal-only RFC, posted as part of URML's Move #16 substrate-spine wave (16 engageable RFCs). Sibling RFCs cover Cartographer (RFC-0205 lidar SLAM) and RTAB-Map (RFC-0207 visual-inertial).

Full RFC: https://github.com/URML-MARS/URML/blob/main/docs/rfcs/0206-orb-slam3-outreach.md

URML's manifest will declare perception.slam_substrate: orb_slam3 plus the five operation modes (monocular / stereo / RGB-D / monocular-inertial / stereo-inertial), camera-calibration YAML reference, and ORB vocabulary file reference.

Asks for the UZ-SLAMLab / ORB-SLAM3 maintainers:

1. SLAM-substrate enum value. URML's manifest enum value preference (orb_slam3, orbslam3, uz_orb_slam3)?
2. Five-mode enumeration shape. Monocular / stereo / RGB-D / monocular-inertial / stereo-inertial — URML's manifest field shape: single slam_mode enum or camera_topology + inertial_fusion decomposed?
3. Camera-calibration YAML reference convention. Manifest-declared path or always launch-param?
4. Vocabulary-file declaration. Manifest field for path + size hint? Checksum-bind URML's validate step?
5. GPL-3.0 cross-citation declaration. Should URML's manifest itself declare a license_bind: GPL-3.0 flag so downstream packagers see the constraint at validate time?
6. Adapter home. URML's adapter (if any) would live in a separately-licensed companion package (likely GPL-3.0); URML-side citation only — is this the right boundary?
7. Conformance listing. Would UZ-SLAMLab consider a README link to URML's compatible-runtimes registry (RFC-0014) as a cross-citation entry?
8. Anything else.

Thanks for the canonical visual-SLAM reference everyone learns from.

Ido Yahalomi (URML maintainer, urml.dev, greenvh@gmail.com)

AI-assisted prose, maintainer-reviewed before posting (see VIBE.md). Human-only correspondence available on request.