pacman-u
short form of pacman --upgrade, which upgrades or adds packages
TLDR
This command is an alias of pacman --upgrade
View documentation for the original command
$ tldr pacman upgrade
SYNOPSIS
pacman -U [options] package(s)
DESCRIPTION
pacman -U is the short form of pacman --upgrade, which upgrades or adds packages to the system from local or remote package files. Unlike -S, this operates on package files directly rather than repository packages.
SEE ALSO
pacman(8), pacman-upgrade(8)