[zahlman]

Not really; it can just symlink the base executable and make a few folders and scripts.

    $ python -m venv --without-pip test-venv && du -sh test-venv
    56K     test-venv

[dragonwriter]

Conceptually, a venv has its own executable.

Physically, that can just be a symlink to the system python (or another version that is still potentially shared with multiple venvs.)