Positioning a \fermata over the last bar line

To position a \fermata sign over the last bar line, you must use a specially modified rehearsal mark

\override Score.RehearsalMark
  #'break-visibility = #begin-of-line-invisible

\version "2.24.0"

%% http://lsr.di.unimi.it/LSR/Item?id=1

\relative c'' {
  \override Score.RehearsalMark.break-visibility = #begin-of-line-invisible
  c1 \mark \markup { \musicglyph "scripts.ufermata" }
}