The computation of invariants of linearly reductive group actions requires the use of Gröbner bases. These options allow partial control over the computation performed by invariants(LinearlyReductiveAction) and hilbertIdeal(LinearlyReductiveAction), allowing to terminate the computation after reaching a certain degree. For more information, see gb.
The source of this document is in InvariantRing/InvariantsDoc.m2:703:0.