As long as there never was an official response to how it works I repeat the conversation...

Black Sun wrote: You know I still cannot figure out how the unique improvement Vault of Governance actually works. It says it gives "50% on heroes" and in flavor text says it's for governance, but it does not appear to affect any heroes plural outside of that system's governor. Moreover it only appears to give 50% extra XP on whatever the governor had. So is this something where you actually have to time its construction completion to coincide with as close to leveling up the hero as possible to max out the XP bonus that turn or what?

Frogsquadron wrote: Not sure if it goes to the governor hero, or all governor heroes. I'll pass it on the QA for a quick check, since it's either an incomplete tooltip, or an incorrect one.

Black Sun wrote: Yeah I checked it and I'm pretty sure the way it works is the hero on that system only gets +50% of whatever his XP is. Since the XP resets each level it means you can potentially only get a few extra XP from that bonus. It doesn't appear to affect other heroes so far as I saw beyond them gaining XP for the usual constructions. I am pretty sure it is entirely around the hero on the system it's built but having to actually estimate how much XP he's going to get from build queu .

How does it work (intended)?

Source: THE BIG "how does it work?" THREAD

So it gives them a bonus to whatever XP they HAVE at the time, only counting their current level?  Eek.  Playing around that seems unnecessarily touchy...

I talked to the designers, and it is supposed to be a 50% bonus to all experience gains after it is built. If you have saves where it behaves differently, please share it.

I just checked your save files.

I built a Questioner without the fault, which gave 27XP. Then I built a questioner with the Vault, getting 41XP. That's in line with the 50% bonus gains, as 27*1.5=40.5, which gets rounded up to 41.

The massive bump in XP you gain when the Vault finishes is probably due to the Vault being a pretty expensive building.

Thanks for clarification. I wonder why Black Sun did get to another conclusion, now. By the way, any hint what could prevent me from beeing able to see save games (both failed, local and cloud) what I renamed in another place than save file folder and copied back in this place? The first time this happens to me...

Sadly no. I have had that problem myself and I'm not sure how to resolve it.