user-1: Does any of the coin selection algorithms used in Bitcoin Core use 'tolerance' in it?
Context: Tolerance here is used for the amount that can be added to fees. In case of BnB if the user does not have enough coins, fees can be adjusted to avoid change

user5406: Yes, Bitcoin Core will permit slightly overshooting the selection target when using the Branch and Bound algorithm, as long as the overshoot is smaller than the cost of creating and spending a change output.
In the loop that evaluates input set candidates, the search will backtrack if the selected amount exceeds selection_target + cost_of_change, but if the selected amount is between selection_target and selection_target + cost_of_change, it'll consider the input set a solution candidate. 
You can find the relevant section of code in the function SelectCoinsBnB in src/wallet/coinselection.cpp.

-1: <p>Does any of the coin selection algorithms used in Bitcoin Core use 'tolerance' in it?</p>
<p>Context: Tolerance here is used for the amount that can be added to fees. In case of BnB if the user does not have enough coins, fees can be adjusted to avoid change</p>
 5406: <p>Yes, Bitcoin Core will permit slightly overshooting the selection target when using the Branch and Bound algorithm, as long as the overshoot is smaller than the cost of creating and spending a change output.</p>
<p>In the loop that evaluates input set candidates, the search will backtrack if the selected amount exceeds <code>selection_target + cost_of_change</code>, but if the selected amount is between <code>selection_target</code> and <code>selection_target + cost_of_change</code>, it'll consider the input set a solution candidate. <a href="https://i.stack.imgur.com/D8zEd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/D8zEd.png" alt="enter image description here" /></a></p>
<p>You can find the <a href="https://github.com/bitcoin/bitcoin/blob/c561f2f06ed25f08f7776ac41aeb2999ebe79550/src/wallet/coinselection.cpp#L96" rel="nofollow noreferrer">relevant section of code</a> in the function <code>SelectCoinsBnB</code> in <code>src/wallet/coinselection.cpp</code>.</p>
