Many of the Technical Standards around MiFID II and MiFIR have now been published in the Official Journal of the European Union, effectively completing the legislative process. These include RTS 20, which specifies the details of the Ancillary Activity test, published here as Commission Delegated Regulation (EU) 2017/592, and RTS 21, which specifies how Position Limits are calculated, published here as Commission Delegated Regulation (EU) 2017/591. A full list can be found here on the Orrick blog.
Further information on how any of the rules operate will now be published as Questions and Answers. ESMA have released several over the last few days, including an updated Q+A on data reporting which can be found here. An updated Q+A on commodity derivatives is expected shortly (see here for details of the previous Q+A).