Tree Fetch Modus
The Tree Fetch Modus is a fetch modus which operates your inventory as a binary search tree.
Imagine that each item can have up to two items below it (called its "children") - one on the left and one on the right. The first item you insert becomes the root (top) of the tree. When more items are added to your inventory, the modus starts looking at the root item. If the new item is before the root item (alphabetically) then it looks to the left. If it's after, it looks to the right. If there's an empty space there, the item goes into that empty space. Otherwise, it continues going down the tree until it finds an empty space.
Note: If an item only has one child item, the visual layout of the items doesn't show you whether it's a left child or a right child, since the items move sideways to make space between them.
In leaf mode (the default), you can only access items at the bottom of the tree (i.e. items with no children, called leaves). In root mode, you can only access the item at the top (the root), but if you take it out, all of its children and grandchildren and so on will be Ejected. So maybe you don't want root mode. If you only want to access the first item you put in, a Queue Fetch Modus is better.
This modus is designed for English - United States. It might not operate correctly in other languages, even other variants of English. Singleplayer is probably okay, but in multiplayer your language needs to match the server, and servers always use US English.