In brief
overflow-x controls content extending beyond a block's left or right edge. auto can provide horizontal scrolling when needed.
Useful to know
overflow-x controls content extending beyond a block's left or right edge. auto can provide horizontal scrolling when needed. [1]
For a wide table, apply the constraint to a suitable container and check a narrow screen. This can keep columns readable without widening the whole page. The other overflow axis can also affect the computed behaviour.
Sources
For further detail and to check the information: