Rogue: Optional Class Features

What are these?

The following list are class features that your dm may either allow you to have in addition to the features you gain from your class or they are options that might replace existing class features

Steady Aim

3rd-level rogue feature
As a bonus action, you give yourself advantage on your next attack roll on the current turn. You can use this bonus action only if you haven't moved during this turn, and after you use the bonus action, your speed is 0 until the end of the current turn.