From the Discourse Trust Levels Manual, one of the conditions to the TL3:
Must not have received more than 5 spam or offensive flags (with unique posts and unique users for each, confirmed by a moderator)
Is there a way to find out if I have such flags, and if so, for what posts. This feedback is very useful for understanding which statements cause a negative reaction from other users.
hopefully a moderator would not assign a "spam or offensive flag" to someone without a PM saying so and asking to stop the offensive behavior. So if you did not get any "warning" I would not worry much about it...
but fair ask, that should be transparent and in your profile
(and actual spammers should get banned right away)
Ask a moderator. Other than that, I have no idea.
According to the Summary page you have three. There are actually six in the list but I assume the three is what matters.
Looks like the ones that count are smart-assed / inappropriate replies like "read the book". Seems reasonable someone might object.
In any case, I assume you are below the five threshold.
Where to see it in the Summary? - I don't see any.
The counts may only be visible to moderators.
The Summary is in the expected place...
https://forum.arduino.cc/u/b707
And, thank you, for being such a great member of this community!
Poke my avatar. I've been kicked off several times/weeks for being right.
They are only visible to moderators
BTW how many flags do I have?
Zero.
Do those "flags" expire? E.g. if all of them are older than a year, they no longer prevent you from reaching TL3.
I can't tell. There are definitely flags excluded from the count but the correlation to the date seems weak.
The "documentation" makes no mention of them expiring.
Discourse is open source. Somewhere in there is the answer.
Could you check mine?
Just curious. 
At least one because I flagged my own post.
Zero.
Flags are verified by a moderator, so this one was most likely not taken into account
It seems to me that this is not entirely correct. The number of flags should be visible to the user himself, and even better with a link to what caused this flag.
Otherwise it turns out some kind of secret dossier like the Stasi
I Agree 200%
Discourse is open source. The pull request goes here. Bear in mind, one of their key people is highly opinionated. You'd be well served to first discuss the idea.
I'm sure mine looks like out front at the UN.
@EmilyJane
Not yet. More effort is required. Are you up to the task??? 
Three. All three posts have been deleted.
