This a javascript tool to emulate Custom Fields within the Shopify dashboard. The main use would be for Shopify designers and developers wanting to give their clients a simple way to edit metafields with less confusion.
Do note that there's no interface for a Store Owner to make any new fields using this (simply to avoid explosions) so it's up to you - the developer - to help add them. To add the required metafields you'll need to either use ShopifyFD, the Shopify API, or a metafield app of your choice.
tl;dr Use the Chrome Extension.
The Chrome Extension is simply a helper script that loads the files from here. If you don't run Chrome or just prefer to load via a bookmarklet you can follow the instructions on this page.
A very basic help guide is available.
If this tool makes you look awesome to your paying customer or helped you land that project, consider leaving me a tip.
Add these strings into the value (or key) for added magic. Not all of these work yet so consider them a suggestion only that may change at any time.
"[a]": limit display to articles only
"[c]": limit display to collections only
"[cu]": limit display to customers only
"[g]": limit display to pages only
"[o]": limit display to orders only
"[p]": limit display to products only
"[_c]": mark as a collection field
"[_f]": mark as a file field
"[_i]": mark as an integer field
"[_g]": mark as a page field
"[_p]": mark as a product field
"[_n]": mark as a number field
"[_d]": mark as a date field
"[_co]": mark as a color field