Where is “apt depends” documented?

Question

Where is the sub command "depends" of "apt" documented, especially its output format and the meaning of the pipe symbol in the output?

"man apt" doesn't mention this sub command at all.

Example invocation:

$ apt depends inxi
inxi
  Depends: pciutils
  Depends: procps
  Depends: <perl:any>
    perl
  Recommends: dmidecode
  Recommends: dnsutils
    bind9-dnsutils
  Recommends: file
  Recommends: hddtemp
 |Recommends: iproute2
  Recommends: net-tools
  Recommends: kmod
  Recommends: lm-sensors
  Recommends: mesa-utils
  Recommends: sudo
    sudo-ldap
  Recommends: tree
  Recommends: usbutils
  Recommends: x11-utils
  Recommends: x11-xserver-utils
 |Suggests: libcpanel-json-xs-perl
  Suggests: libjson-xs-perl
  Suggests: libxml-dumper-perl
 |Suggests: wget
 |Suggests: curl
  Suggests: libhttp-tiny-perl
    perl

Answer 1

It is documented on apt-cache manpages :

depends pkg...

depends shows a listing of each dependency a package has and all 
the possible other packages that can fulfill that dependency.

The meaning of the pipe | is or , in your example:

 |Suggests: wget
 |Suggests: curl
  Suggests: libhttp-tiny-perl

can be translated to:

Suggests: wget or curl or libhttp-tiny-perl

And

 |Suggests: libcpanel-json-xs-perl
  Suggests: libjson-xs-perl

can be translated to:

Suggests: libcpanel-json-xs-perl or libjson-xs-perl