Another hidden gem of groff's treasure chest: It is possible to control the width of \| and \^ on a per-font basis. If the font definition file of the current font contains entries for `\|' and `\^', respectively, the specified widths are used instead of the default values. [Normally, a font definition file contains a single glyph name starting with a backslash, namely `\-'.]
I've discovered this right now because I had to fix a nasty bug with \| and \^ for -Thtml and -Tutf8 (which emitted a space instead of ignoring them). Users of the CVS, please upgrade. Werner