Bugzilla

I've learned about yet more attributes that the tree view tables should have:
- [aria-rowcount](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Attributes/aria-rowcount) for the total number of rows in the table, given that some will not be a part of the DOM if the number of rows is high
- [aria-rowindex](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Attributes/aria-rowindex) to correctly set the index of each row
- [aria-sort](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Attributes/aria-sort) to tell screen readers which column is the sorted one

I wonder if the header row should be included in the row count if it is visible. I suspect the answer is "no" and there's a better way to label it, but I've heard screen readers say some weird things when talking about the header row.

While I'm here I'm going to add an aria-label to each column header cell as otherwise the readers use all of the text they can find inside the cell, as the label. And that sounds bad, especially if the column picker is visible, since it's inside one of the cells.

I've learned about yet more attributes that the tree view tables should have:
- [aria-rowcount](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Attributes/aria-rowcount) for the total number of rows in the table, given that some will not be a part of the DOM if the number of rows is high
- [aria-rowindex](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Attributes/aria-rowindex) to correctly set the index of each row
- [aria-sort](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Attributes/aria-sort) to tell screen readers which column is the sorted one

I wonder if the header row should be included in the row count if it is visible. I suspect the answer is "no" and there's a better way to label it, but I've heard screen readers say some weird things when talking about the header row.

While I'm here I'm going to add an aria-label to each column header cell as otherwise the readers use all of the text they can find inside the cell, as the label. And that sounds bad, especially if the column picker is visible, since it's inside one of the cells. Or for the column headers containing only icons in about:3pane.