}
		if {[llength $argv] > 1} {
			set cpu [lindex $argv 1]
		}

		puts "Extensions available for OS=$os, CPU=$cpu:"

		set extsinfo [::teapotclient::get_extensions $teapotservers $os $cpu]
		foreach {ext extinfo} $extsinfo {
		array set exts [::teapotclient::get_extensions $teapotservers $os $cpu]
		foreach ext [lsort -dictionary [array names exts]] {
			set extinfo $exts($ext)

			set extvers [list]
			foreach extinfoitem $extinfo {
				set extinfoitemvers [lindex $extinfoitem 0]
				if {[lsearch -exact $extvers $extinfoitemvers] == -1} {
					lappend extvers $extinfoitemvers
				}
			}