I don't believe that is correct at all and ask for evidence to support that position. I have some speculation and "reading between the lines" in my comments below, but generally you can find many statements from Red Bull/RBPT and Honda to back up my narrative.
At the very start of the partnership after Honda pulled out, there was lots of talk and public statements about RBPT taking more ownership of the power units including I believe assembly in RBPT locations. However this evolved with that level of transfer of responsibility to RBPT not happening and Honda continuing to own ongoing R&D, production, trackside support, etc. This was also discussed publicly by RBPT and Honda. Some of this pivot might be driven by the need for RBPT to be a "new" power unit supplier. In hindsight this was the start of an amicable divorce between RBPT and Honda. So really, while it's (meaning the current engine to run through end of 2025 season) run under the RBPT name, it's probably all or nearly all really Honda under the covers. Today, RBPT is focused building up their team and on 2026.
Many have broadly assumed that RBPT just somehow obtained the Honda power unit IP from Honda and it would be the basis for the 2026 RBPT solutions. No doubt RBPT has learned quite a bit from Honda, but in the end there is RBPT IP and Honda IP. They may even have some level of cross licensing. And that licensing (particularly around Honda to RBPT) is probably only through 2025, but either side will not give it away. They might sell it, but as both are serious about 2026, Honda is not going to do an IP deal with RBPT and vice versa. And even then, while RBPT can use the Honda engines today, I doubt the licensing is no more than "use of the product" and not full technical details. In short Honda has kept their "secret sauce" secret.
I expect that many thought that if Honda was coming back (if they really left) in 2026, they they would partner with RedBull. The problem is... Red Bull is committed to building their own units and not being beholden to someone else to provide power units. They want to play equal to Mercedes, etc. There was no 2026 Red Bull/Honda pairing even if they have had (and continue to have) an excellent partnership. Honda probably understands this so the two partners will just have to work in a more controlled fashion between now and 2026. Probably this is not a "now" thing, but probably has been accelerating over the past 12+ months. In short, it's no different than any other customer team. Customers don't know internal details of the engines provided to them.
This article talks to some of this...
https://racingnews365.com/chinese-wa...fter-ford-deal
Richard