Clause 18 of the bill amends section 117.1 of the Income Tax Act. The act contains a number of amounts that are indexed to inflation, and section 117.1 provides the indexation of various amounts listed in that provision.
What the amendment does is that first it reorganizes subsection 117.1(1), because it used to be a bit hard to read, and it sets out all the different things in the act that are indexed to inflation and what their starting indexation value was.
The actual amendment is consequential on the adjustments to the Canada workers benefit. In particular, certain amounts under the Canada workers benefit are indexed to inflation. What this would do is provide indexation of those amounts—for example, the new $14,000 threshold for spouses.