What is the la command?

From .bashrc file in your home directory, we have these aliases:

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

la is just an alias of ls with just the -A option.

From man ls

ls -alF

   -a, --all
          do not ignore entries starting with .

   -l     use a long listing format

   -F, --classify
          append indicator (one of */=>@|) to entries


ls -A

   -A, --almost-all
          do not list implied . and ..

By default la is an alias for ls -A. In contrast to just ls it doesn't omit files starting with a dot, except for . and ..