install tlgpg fails

I'm trying to understand why this fails (and perhaps other things as well; I haven't tried). This is BasicTeX 2026 on an Intel Mac.

$ sudo tlmgr --machine-readable --repository https://texlive.info/tlgpg/ --persistent-downloads install --reinstall tlgpg
start load https://texlive.info/tlgpg/
finish load https://texlive.info/tlgpg/
location-url	https://texlive.info/tlgpg/
total-bytes	770172
end-of-header
tlgpg.universal-darwin	i	-	18	769604	??:??	??:??	-	-	-
TLPDB::_install_data: unsupported container format xz for https://texlive.info/tlgpg/archive/tlgpg.universal-darwin.tar.xz
tlgpg	i	-	23	568	00:00	00:00	-	-	-
TLPDB::_install_data: unsupported container format xz for https://texlive.info/tlgpg/archive/tlgpg.tar.xz
end-of-updates
tlmgr: package log updated: /usr/local/texlive/2026basic/texmf-var/web2c/tlmgr.log

I'm puzzled because the xz binary exists and at least --help works.

$ file /usr/local/texlive/2026basic/tlpkg/installer/xz/xz.universal-darwin 
/usr/local/texlive/2026basic/tlpkg/installer/xz/xz.universal-darwin: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64:Mach-O 64-bit executable arm64]
/usr/local/texlive/2026basic/tlpkg/installer/xz/xz.universal-darwin (for architecture x86_64):	Mach-O 64-bit executable x86_64
/usr/local/texlive/2026basic/tlpkg/installer/xz/xz.universal-darwin (for architecture arm64):	Mach-O 64-bit executable arm64

thanks,
Adam