@tsteur I have simplified the PR. The additional columns will now only be requested by the sparkline visualization and thus won't occur in any API output.

I've put it for now into 4.9. I had a quick look and it looks OK but I can't do a full review due to time. Be great for someone to do later a full review

This issue is in "needs review" but there has been no activity for 7 days. ping @matomo-org/core-reviewers

@diosmosis It seems the test I had added to this PR starts failing after #18761 has been merged in. The sparklines lost their color. See https://builds-artifacts.matomo.org/matomo-org/matomo/fixcomparisontrend/54586/Comparison_visits_overview_widget_sv.png

I guess the javascript method to initialize the sparklines is called before the colormanager, which is in Vue, has been loaded fully. The sparline requests contain "lineColor":[null,null]
Would you mind having a look and maybe pushing a fix on this branch?

@sgiehl that's weird, ColorManager is still in vanilla JS. I'll take a look.

@sgiehl should be fixed