HTML customisations in the OpacMoreSearches location don't seem to appear on the OPAC anywhere. I'd expect them to replace the section under the searchbar but I don't think anything happens.
OPACMoreSearches is added at the end of the navigation bar below the simple search. This still works as it should, but I think you have run into a known bug here: Bug 31450 - HTML customizations and News will not display on OPAC without Publication date *** This bug has been marked as a duplicate of bug 31450 ***