A long and interesting interview with Dr. Marko (in German).
English summary by Marklar from the Autosport forums:
-Development ahead of schedule, rollout on the 12th february
-Disagrees with Renault's take on the current order of the engines: he thinks Renault is only better on some high engine modes (like in Monza) and reliabilty counts too
-They plan with 3 engines for 2020
-He thinks with Ricciardo they would have probably finished 2nd in the WCC (later in the interview he said certainly)
-Ricciardo's departure was a shock, not only because he is a great driver but because he is a funny dude and there was a less fun buzz in the team without him
-He won two bets again Cyril and Ricciardo: against Cyrill that Toro Rosso will finish at least twice ahead of them, and against Ricciardo before Austria that they will have the engine with the better reliability
-Reckons that Gasly was strongly affected by the test crashes and by the fact that Max was simply quicker. He then tried to solve his deficit too much over set-up work/technique
-He is very happy about Albon's race performance, qualifying needs improvement. And he finds it curious that he did the worst on the tracks he knew the best. He thinks he can be closer this year.
-He says that Verstappen has - if everything goes normal - no exit clause (interviewer then asked if its about being top 3 in the WCC, he then replied that they have a contract with Honda till 2021 and that they need a "competitive engine")
-The extension of Max happened quite quickly after Honda extended for 2021 and they wanted full focus on 2020 and contiunity.
-Target is to become with Max the youngest WDC of all time
-In his opinion Max and Lewis are the outstanding drivers atm, Leclerc is getting there and he isnt writting off Vettel either if he has a certain car and support.
-It was clear to him that Max was special after that F3 race at the Norisring where he was 2s quicker than everyone else. At that point they were negotiating where Max would race in 2015, and after that he decided to put him into F1, which was a surprise for Jos.
-Max' biggest weakness at the beginning was his patience. He made a huge step in 2019 and he only showed glimpses of this in Monza/Spa. He doesnt count Mexico to this, that was more lacking diplomacy, which he will learn.
-He likes Max' straight forward attitude, and it also fits to the Red Bull brand, but for a championship fight you need to tone it down a bit, and he knows it.
-Mexico was a bit unfortunate, because his press officer didnt knew that he was under investigation, so he wasnt prepared for this question.
-He is happy about the measures the FIA took on the engine matter (though what happened with the Leclerc incident in Abu Dhabi was pretty BS)
-Reckons that the matter is settled with the new fuel flow sensor, but engineers are creative enough to find new solutions, so it might not be.
-Wasnt surprised about Leclerc's extension, but he doesnt think that Ferrari is his team yet, Vettel can still strike back if he has the car, but he needs to go out of his comfort zone and fight (politically), he is not sure if Vettel has the motivation for this
-Cant imagine Vettel at Red Bull now that they extended with Verstappen, especially financially (he first said because of the budget cap, but then is told that salaries dont count, then talks about how it would be better if it was)
-When he is asked about whether Verstappen is the most expensive Red Bull driver of all time, he said that the basic salary is relatively small but the bonusses are huge at Red Bull, and with that Max could indeed become the most expensive one
-Alonso is a no-go, because of Honda and because Red Bull's philosophy is to have their own young drivers.
-He thinks the F1 field will only converge in 2022/23 because initially the big teams will carry over their advantage. No matter what happens he praises Liberty for trying it.
-Doesnt think that they will have to fire too much staff (could move them to Red Bull Technology, etc.), but they will certainly have less agency workers
-Would prefer to ditch telemetry so that the driver matters more and that there is more unpredictability in terms of reliability. Would also save money.
-He changed his stance on the F1 Power Unit, things have changed in the society in the last years (in terms of environmentalism) and the engines are magnificent in this aspect marketing wise, but they failed to promote this properly
-He thinks Formula E is a great marketing platform, but F1 is a whole different level (was asked about whether he would advice Red Bull to race in FE)
-Confirms that they were talking with Volkswagen, but that was before the Dieselgate. Then everything changed.
-Confirms that Lauda promised him a Mercedes engine, but then was overruled.
-He doesnt think that a different prize money distribution will change things massively: in the end the quality and dynamic of the staff matters more
-About the next concorde agreement: no team has signed yet, there are some more points that need clarification, especially on the budget cap (how it's going to be policed, especially with Ferrari being a special case in the books)
-Next concorde agreement wont be as long as in the past, and if they dont have a engine it's a legit reason to leave (he was asked if signing a new agreement would mean that Red Bull stays for sure all the way)
-Thinks Mercedes with Hamilton are favourites, but they are well-prepared. To challenge they have to be competitive (not necessarly quickest) everywhere.
-He is glad that they keep the 2019 tyres and thinks they are understanding the tyres better now (cant guarantee it though). Also implies that Mercedes with their know-how and Hamilton with his experience have an advantage on understanding tyres in general.