Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: File Format
GLTFEXPORTER_FILEFORMATParameter: Current Frame
GLTFEXPORTER_CURRENTFRAMEParameter: Custom Frame
GLTFEXPORTER_CUSTOMFRAMEParameter: Transform
GLTFEXPORTER_PSRANIMATIONSParameter: Morph
GLTFEXPORTER_MORPHANIMATIONSParameter: Skin
GLTFEXPORTER_SKINANIMATIONSParameter: Bake Animation
GLTFEXPORTER_BAKEANIMATIONSParameter: Textures
GLTFEXPORTER_TEXTURESParameter: Width
GLTFEXPORTER_TEXTURES_WIDTHParameter: Height
GLTFEXPORTER_TEXTURES_HEIGHTParameter: Resize Textures
GLTFEXPORTER_TEXTURES_RESIZEParameter: Double Sided
GLTFEXPORTER_DOUBLESIDEDParameter: Cameras
GLTFEXPORTER_CAMERASParameter: Instances
GLTFEXPORTER_INSTANCESParameter: Normals
GLTFEXPORTER_NORMALSParameter: UVs
GLTFEXPORTER_UVSParameter: Flip Z
GLTFEXPORTER_FLIPZ