If we implement IERS data handling, how'd you implement the constantly changing data?
I can imagine having a user preference to enable/disable UT1 calculations based on IERS data.
If UT1 calculations are disabled, a displayed time can be suffixed with [UT1 disabled - currently displayed as UTC].
If enabled but IERS data file is not present or does not contain data for a currently displayed time, there could be a suffix like [Earth orientation data not available - currently displayed as UTC - goto/click xyz to download].
Martin