Is this about the doc-tagged https://lsr.di.unimi.it/LSR/Item?id=803 ?
Isn't it more that StringNumber _may_ be needed, like
%% proposal:
Slides for chords are indicated by default in both Staff and TabStaff.
String numbers may be necessary for TabStaff because automatic string
calculations are different for chords and for single notes.
myMusic = \relative c' {
<c e g>1 \glissando <f a c>
<cis, eis gis>1 \glissando <f a c>
<cis eis gis>1 \glissando <f a c\3>
}
\score {
<<
\new Staff {
\clef "treble_8"
\omit StringNumber
\myMusic
}
\new TabStaff \myMusic
>>
}