The saved resourcepacks will be in your default resourcepacks folder.
This Mod adds a button next to your resourcepacks button that allows you to download server resourcepacks.
On any server that has a resourcepack, open the Pause Menu and press Options. Next to the Resourcepack button should be a small download button. It will download the Servers Resourcepack into your default resourcepacks folder. 
Use the command
/srd autoDownload <true|false>
to enable or disable automatic resourcepack downloading. If enabled, resourcepacks will automatically be downloaded upon joining a server.
The Fabric API is required for this Mod to work. It can be downloaded here.
