Yes and no; there are some binary files too, but there are ~534MB of JavaScript code mixed with additional assets. Once you extract the content from the archive (using the tar.gz version) you will find a directory with multiple sub-directories and files that roughtly weighs 636MB distributed like this:

    9.1M - content_shell.pak
    60M  - goterminal
    9.8M - icudtl.dat
    4.0K - INSTALL
    2.5M - libffmpeg.so
    18M  - libnode.so
    20K  - LICENSE
    352K - locales
    404K - natives_blob.bin
    536M - resources
    604K - snapshot_blob.bin

The directory "resources" contains the ASAR file plus another sub-directory named "app" that contains the assets and the "node_modules" tree, this directory alone weighs 534MB because of the 720 NPM packages required by the application.