Cloned it locally, used 'wc' to do the work:

    /tmp/tmp.KVE7aSEvue/brave-core/patches $ wc -l *.patch | sort -rh | head
      8879 total
       172 third_party-blink-renderer-modules-webgl-webgl_rendering_context_base.cc.patch
       112 chrome-BUILD.gn.patch
       104 chrome-installer-linux-debian-build.sh.patch
        76 chrome-android-java-AndroidManifest.xml.patch
        72 components-vector_icons-aggregate_vector_icons.py.patch
        68 chrome-android-BUILD.gn.patch
        61 chrome-installer-linux-BUILD.gn.patch
        57 chrome-browser-resources-settings-privacy_page-personalization_options.html.patch
        55 net-socket-socks5_client_socket.cc.patch

All together, nearly 9000 lines of patches. The largest currently is 172

Sure, some of this is inflated by the context of nearby lines - but we don't get to ignore those, patches must play nice.

Cumulatively they have 8879 lines of patches, the largest being 172

    /tmp/tmp.KVE7aSEvue/brave-core/patches $ wc -l *.patch | sort -rh | head
      8879 total
       172 third_party-blink-renderer-modules-webgl-webgl_rendering_context_base.cc.patch
       112 chrome-BUILD.gn.patch
       104 chrome-installer-linux-debian-build.sh.patch
        76 chrome-android-java-AndroidManifest.xml.patch
        72 components-vector_icons-aggregate_vector_icons.py.patch
        68 chrome-android-BUILD.gn.patch
        61 chrome-installer-linux-BUILD.gn.patch
        57 chrome-browser-resources-settings-privacy_page-personalization_options.html.patch
        55 net-socket-socks5_client_socket.cc.patch

Not insurmountable, but not as easily hand-waved, either.

One might say -- "but a lot of that's just context!"

Those are significant lines of code that these changes must play nicely with. There's actually more, these numbers do a disservice to everyone