It's very highly recommended to not use these files, but rather use the pre-built library as found in e.g. the /build, /web, and /image_decoders folders in the root of this repository.

Please note that the “lib” build target exists mostly to enable unit-testing in Node.js/Travis, and that you'll need to handle e.g. any necessary polyfills and/or Node.js dependencies yourself if using the files in this folder.