According to the kde.org documentation for KMail filter setup

If the regular expression editor is installed then you can edit the regular expression by clicking on the Edit... button.

I think the editor is called KRegExpEditor, and should be included in kdeutils. Although I have the kdeutils package installed I have no regexp edit button, nor can I find kregexpeditor anywhere.

Is still part of KDE, & what can I do to get it back? I am on KDE 4.4.5 / Fedora 13 / kernel 2.6.33.

Thanks,
Andrew

As best as I can tell it's not been ported to kde4 and there is this Fedora bug
https://bugzilla.redhat.com/show_bug.cgi?id=445699 which confirms it's not there and won't be fixed

When I look @ kdeutils4 I see no executables

The author of KRegExpEditor was very busy with studying for the last couple of years. He recently graduated and says he wants to return attention to KRegExpEditor and other software he had been working on.

Cheers,
_