Use no Debian/Ubuntu:
curl -fsSL https://a11ydevs.github.io/emacs-a11y/debian/a11y-emacs-archive-keyring.gpg | sudo tee /usr/share/keyrings/emacs-a11y-archive-keyring.gpg >/dev/null
echo "deb [signed-by=/usr/share/keyrings/emacs-a11y-archive-keyring.gpg] https://a11ydevs.github.io/emacs-a11y/debian stable main" | sudo tee /etc/apt/sources.list.d/emacs-a11y.list
sudo apt update
sudo apt install emacs-a11y-config emacs-a11y-launchers