A number of table headers in pack-spec.md are incorrect. These errors are showing up as "serious" in accessibility checkers.

In the table row at about line 450, check out b3 and second v in these lines

<td headers="integer_encoding_scheme_v">1024</td>
<td headers="integer_encoding_scheme_b0">192</td>
<td headers="integer_encoding_scheme_b1">13</td>
<td headers="integer_encoding_scheme_b3">&nbsp;</td>
<td headers="integer_encoding_scheme_v">&nbsp;</td>
<td headers="integer_encoding_scheme_b4">&nbsp;</td>

In the tables Example 1,2, 3 starting at line 3587, there are no table header cells, and the id's used in the headers attribute are not defined in the same table.
See this page for details on the applicable rules:
https://dequeuniversity.com/rules/axe/3.0/td-headers-attr?application=webdriverjs