With a big mod list it can sometimes be confusing how to get items and where they are used. This mod adds a button to the top of the screen where you can drop items to find out how to get them and where to spend them. Click with an empty hand to open a drop-down menu for fluids.
There also is a shortcut (Ctrl+f by default) to search the current item in your hand or open a search bar when your hand is empty.
Click on recipes listed in the mod GUI to get more details: all the ingredients and products, as well as the machines that can be used for crafting it. Click on items in the recipe pane to investigate further.
This is a fork of the original 'What is it used for?' mod by Mr Doomah, updated for newer Factorio versions and with additional features.
Please use the What is it used for? forum thread for feedback.