All metapackages for all variants are documented in REP 142: ROS Indigo and Newer Metapackages.
If you'd also like to know all system dependencies that will be installed (and you're using apt-get), then (from man apt-get):
APT-GET(8)
apt-get - APT package handling utility -- command-line interface
...
-s, --simulate, --just-print, --dry-run, --recon, --no-act
No action; perform a simulation of events that would occur but do not actually change the system. Configuration Item: APT::Get::Simulate.
so running any apt-get install command with the -s switch will only simulate what would happen, and should let you inspect what particular set of packages will be installed without actually installing them. One-liner: sudo apt-get install -s $some_pkg | grep Inst | awk '{ print $2 }'.
You might also just select n when asked by apt-get install whether you want to continue (which it asks before installing anything).
