What is `local storage` as opposed to `storage`

Question

From solidity docs (https://docs.soliditylang.org/en/v0.8.4/types.html#data-location ) -

Every reference type has an additional annotation, the “data location”, about where it is stored. There are three data locations: memory, storage and calldata. Calldata is a non-modifiable, non-persistent area where function arguments are stored, and behaves mostly like memory.

Further down in the docs it says this:

Assignments from storage to a local storage variable also only assign a reference.

What is local storage ? How is it different from storage

Before you close this down as duplicate , I have read the other answers and none of them answer this comprehensively .

Answer 1

Local storage references to storage variables inside a function, which also allows data manipulation.

Better understand with this code example:

contract Example {
    // State variables (storage)
    uint256[] public myArray;
    mapping(address => uint256) public myMapping;

    struct MyStruct {
        uint256 x;
        uint256 y;
    }
    MyStruct public myStruct;
    function setValues() public {

        // Local storage references for reference types
        uint256[] storage localArray = myArray;
        mapping(address => uint256) storage localMapping = myMapping;
        MyStruct storage localStruct = myStruct;

        // Modify values through local storage references
        localArray.push(1);
        localMapping[msg.sender] = 100;
        localStruct.x = 10;
        localStruct.y = 20;
    }
}

You can see we are not directly updating the storage variable, instead, we are updating the local reference and it also updates the original storage variable.