Excellent... no more squinting! I was sick and tired of having to press Ctrl+(numberpad plus sign) on my laptop PC to zoom-in every single time I loaded a new website or page. What's more is that this was a persistent problem, and I needed to make this change across-the-board. I needed **one default zoom** for everything for every website I visited. This solves that problem, is lightweight code, and does its job well.
One more thing I discovered after using this extension: refreshing a page does not automatically update it to the default zoom you set using this extension, but closing a tab and then immediately reopening it does. This is a good behavior because there are times when a page needs to be refreshed without resetting it back to the default set by this extension. If you need that, then simply close and then re-open the tab using Ctrl-W (close) and then Ctrl-Shift-T (reopen), after which the default will be restored for that tab.