There are many articles with wikitables that have manually numbered rows. If you add one row somewhere in the middle, you have to change all the numbers of the second half of a table.
Now, as we know sortable and collapsible functions of wikitable, there could also exist numbered function. Writing {| class="wikitable numbered" would make an additional "#" column with numbers. Of course, that function would be available just in simple tables without rowspans and colspans.
@Janezdrilc: Thanks for reporting this. As you assigned this task to yourself, do you plan to work on writing code to fix this?
Also, can you please provide at least one example link to an article "with wikitables with manually numbered rows"?
Sorry for assigning my self - my mistake (no programming skills). Here is an example of a list I've made, before I had to remove numbers for the reason of updating:
Numbered wikitables should be equivalent to ordinary numbered lists using "#".
There is already a task for this. It has a solution, I believe, but for some reason unknown to me, it is not being implemented. See:
T42618. jquery.tablesorter: Add support for a "fixed" column of row numbers.
*https://phabricator.wikimedia.org/T42618