Ok. So question... Was the @blurtbooster account ninja mined?

There is no such thing as "ninja mined" on Blurt.

Ninja mining refers to the early days of Steem when it was a POW blockchain and it was possible to mine STEEM.

Blurt has never had POW mining. It was forked from Steem version 0.22. The accounts , keys, and balances were copied over. It was the intention to not bring over any of the balances that belonged to Steemit, but due to some error, some of the Steemit stake made its way over. The founders discussed what to do with it. They were thinking of burning it, but then decided to put it in the @socialgraph account to be used for funding development on Blurt. This information is all public on GitLab and on the Blurt blockchain (see https://gitlab.com/blurt/blurt/-/issues/25).

To answer your question (and then some), here's a summary of @blurtbooster's history:

The @blurtbooster account was created on January 23, 2022 by @socialgraph.

Originally, it was meant to replace the get-upvotes bot in the Blurt Discord server, so it was given a delegation of 100 kBP.

That bot didn't get finished, but it was turned into something else later, which I will come to later in this reply.

Around the same time (mid to late January of 2022), the @symbionts team had written a Discord bot for creating "free" accounts for people who came to the Blurt Discord server and could verify themselves. And since the @blurtbooster account was just sitting there doing nothing, we decided to use it for account creation with the Discord bot from the @symbionts team. It was given a balance of 1000.000 BLURT that was meant to pay for the created accounts.

Later on, we saw that people seemed to like what ctime was doing by voting all the posts, so we had the idea to do something similar. A bot was created that would vote for all the posts as long as an account isn't in COAL and it passed a few more checks. Then it was given a bigger delegation. The goal was to spread the votes around.

It was also meant to be a way to delegate your BP if you're not using it, and it pays back 80% of the curation rewards to the delegators like curation projects on Hive and Steem do (the remaining 20% stays in the @blurtbooster account in order to subsidize "free" account creation with the Discord bot). So after that part was added, it was possible to delegate to @blurtbooster and get paid the curation rewards from the posts your stake was used to vote on.

Now, it's true that a huge chunk of the delegations comes from the foundation's accounts (@socialgraph, @initblurt, @instablurt, @blurtmob), and I think this is where the claims of "fake stake" come from (since those accounts got their funds from the Steemit stake that was accidentally brought over at the time of the fork). The curation payments that comes from @blurtbooster to those accounts are used for paying the core team, so the funds are still being used to fund development as it was originally intended to be used. You can check @blurtbooster's incoming delegations to confirm what I'm saying here: https://blurtwallet.com/@blurtbooster/delegations

Since some on the chain figured out the algorithm, they started creating garbage posts that would maximize their votes from @blurtbooster (since a dumb bot can't tell the difference between a good post and just garbage filler text and images). After adding some more checks and safeguards, those who were just abusing kept figuring ways to bypass the safeguards and kept milking the bot's votes.

That's when it was decided that @blurtbooster would switch over to a whitelist model. That's where that Discord bot that was started to be written at the beginning but never finished came in handy. The Discord bot was repurposed to be used for managing the whitelist. There is a private Discord channel where about a dozen people have access to add or remove accounts from the whitelist.

Anyway, it's a bit of a long-winded reply, but I hope it answers any questions you had about @blurtbooster.

If you have any more questions, you can always direct your questions at @blurtbooster. And you can always look at the activities of the @blurtbooster account on one of the explorers (https://ecosynthesizer.com/blurt/@blurtbooster, or https://blocks.blurtwallet.com/?#/@blurtbooster). The ecosynthesizer explorer has some filters where you can see only the activities that you want to see.

Have a good one!