v.lrs.where
Finds line id and real km+offset for given points in vector map using linear reference system. 
Vector (v.*)
QgsProcessingParameterVectorLayer|lines|Input vector map containing lines|1|None|False
QgsProcessingParameterVectorLayer|points|Input vector map containing reference points|0|None|False
QgsProcessingQgsProcessingParameterVectorLayerLayer|rstable|Name of the reference system table|False
QgsProcessingParameterNumber|threshold|Maximum distance of point to line allowed|QgsProcessingParameterNumber.Double|1000.0|True|0.0|None
QgsProcessingParameterFileDestination|output|LRS Points|Txt files (*.txt)|None|False