This is PKGBUILD for swow
You may clone this via github or aur and use makepkg
to make archlinux packages
# clone it
git clone https://github.com/swow/PKGBUILD php-swow
# cd into it
cd php-swow
# make package
makepkg -Cf
# install it
pacman -U php-swow-<ver>.tar.zst
Or, use an aur helper
yay -S php-swow
# or
aurman -S php-swow