Man pages matching name expr in section 3tcl:

expr.3tcl.pl	debian 10 / manpages-pl-dev
expr.3tcl.zh_CN	debian 10 / manpages-zh
expr.3tcl.zh_TW	debian 10 / manpages-zh
expr.3tcl.en	debian 10 / tcl8.6-doc
expr.3tcl.zh_CN	debian 11 / manpages-zh
expr.3tcl.zh_TW	debian 11 / manpages-zh
expr.3tcl.en	debian 11 / tcl8.6-doc
expr.3tcl.zh_CN	debian 12 / manpages-zh
expr.3tcl.zh_TW	debian 12 / manpages-zh
expr.3tcl.en	debian 12 / tcl8.6-doc