From what I can tell, there is no -labelFont option for CollapsableFrame. However, you can try directly accessing the Label widget used for the title with: 
my $cf = $pane->CollapsableFrame(...);
$cf->{ident}->configure(-font => '{Times} 10 bold');

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In reply to Re: change title font in collapsable frame by pc88mxer
in thread change title font in collapsable frame by lil_v

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