Not by UEFA, but by the Romanian FA.
Original article in Romanian. Main points below.
Assuming all 53 FAs will participate - there will be 8 groups of 6 teams and one of 5 teams.
The teams will be split in 6 pots according to the UEFA coefficient. This list doesn't appear in the FRF article, is based on my calculations.
Pot 1: Spain, Germany, Netherlands, Italy, England, Portugal, Greece, Russia, Bosnia-Herzegovina
Pot 2: Croatia, Ukraine, Sweden, Denmark, Switzerland, Belgium, Czech Republic, Hungary, Republic of Ireland
Pot 3: Serbia, Turkey, Slovenia, Israel, Norway, Slovakia, Romania, Austria, Montenegro
Pot 4: Armenia, Poland, Scotland, Finland, Latvia, Wales, Bulgaria, Estonia, Belarus
Pot 5: Iceland, Northern Ireland, Albania, Lithuania, Moldova, FYR Macedonia, Azerbaijan, Georgia, Cyprus
Pot 6: Luxembourg, Kazakhstan, Liechtenstein, Faroe Islands, Malta, Andorra, San Marino, Gibraltar
The schedule for each group will be determined by the computer, not by the football associations.
These are the principles used to determine the schedule:
- Team won't play more than 2 games consecutively at home (or away)
- Each team will start and end the competition with a home-away (or away-home) double.
- For countries with long winters - these teams will play away on match days 4 and 5 (November and March)
b) Venues with climate risk
- Stadiums belonging to FAs from countries with cold winters are in this category
- In a group there will be at most 3 teams from countries with cold winters. There are two subcategories: Very cold winter (Finland, Faroe Islands, Norway and Russia) and Cold winter (Andorra, Belarus, Estonia, Lithuania, Latvia, Sweden and Ukraine).
- The objective is to avoid long distances when playing two matches in the same FIFA window.
- Based on the distances between the capitals of the countries involved, the transport links can be: conditioned ( flight time > 8 hours), semi-conditioned (between 6 and 8 hours) and unconditioned (less than 6 hours).
- In a group there will be at most 3 teams from countries that involve long distances.
d) Political situation
No Armenia/Azerbaijan, Russia/Georgia, Spain/Gibraltar.
e) TV rights
England, Spain, Germany, Italy and the Netherlands will play in groups of 6 teams.
f) Constraints and preferences
Constraints are more important than preferences.
Order of priority for constraints: Cold winter (1), transport distances (2), specific restrictions (3), reasonable kick-off time (4).
Order of priority for preferences: top TV markets (6), late kick-off time (7), regional spread (7), equal spread of matches/kick-off times (9).
Yes (I know, there's no 5 and 8, while 7 appears twice, but that's how it's in the FRF article).
Games will take place Thursday-Sunday or Friday-Monday or Saturday-Tuesday from 20:45 CET. In weekends the kick-off could be at 18:00 CET.