Just to amplify a bit,
Some of these files are "duplicates" -- that is, they have
the same text content -- but code is customized for browsers other
than IE and for IE browsers earlier than 5.5. There may be some
differences between IE 5.5 and IE 6; I'm not sure.
And you shouldn't assume that the latest IE browsers refer
only to the whxdata folder. As Peter says, you would need thorough
testing.
Finally, as a reminder and for forum readers who may not have
seen this advice:
Each merged project has its own set of these three folders,
which the master project uses to assemble TOC, Index and Search
databases on the fly. So even though they have identical names,
they are not duplicate or redundant. Let them be.
Harvey