See https://bugzilla.mozilla.org/show_bug.cgi?id=1673345#c0 for more context.

If the singleTap query fails due to an AbortError, we will assume the command was successful and will silently return null. The goal of this bug is to try to better track the completion of the command so that we can decide if it needs to be retried with the next JSWindowActor pair.

As mentioned while reviewing the patch on bug 1671347 this command is only used internally by some harnesses / tests that cannot use the WebDriver actions yet. We hope to have this done soon, so fading out support for this command is what I would like to see, and maybe marking this bug as wontfix. But lets not do that now, but wait until all Marionette based automation runs with actors by default.

This is a legacy command and not used anymore with Marionette. I filed bug 1792529 to get it removed.