I like how this has keyword "easy" :-) Yet I also don't plan to pursue this.

I currently don't plan to pursue this. Silvan, what about you? If not, feel free to close this.

Changing these to lower-case works for me. Ideally, we should also check configurations in our wiki documentation and in the driver script for consistency.

We currently mix upper and lower case versions. Silvan and me are in favor of converting everything to lower case. An imperfect grep with pattern '"[A-Z][A-Z]' and the C locale finds upper-case enum options in:

src/search/cegar/additive_cartesian_heuristic.cc
src/search/cegar/subtask_generators.cc
src/search/lp/lp_solver.cc
src/search/merge_and_shrink/label_reduction.cc
src/search/merge_and_shrink/merge_tree_factory_linear.cc
src/search/merge_and_shrink/shrink_bisimulation.cc
src/search/merge_and_shrink/shrink_fh.cc
src/search/operator_cost.cc