How to unzip using fetch API

I've followed the documentation of Fetch API in https://emscripten.org/docs/api_reference/fetch.html
to fetch the contents from my local server in "https://xxx/text_rendering.glb.gz"

The fetch api returns 364155 bytes of data

What i want to achieve is to get the glb buffer.. i guess i might need to unzip to get the buffer or it returns the unzipped buffer?

Can anyone help with this?