Thank you. That's news to me. Have all the major pools supported it?

Although I too don't think it was stolen, you're wrong.
nSequence = 0xFFFFFFFE, so no RBF, so nothing the owner could do once the tx is broadcasted.
doesn't matter if it gets mined in a block or two, or 20.

what is the current state with vouchers?

v2 version says they're valid on v3
v3 version says "Old vouchers will be available at Segwit version after few days"

It is for people who generate their transactions manually and would like them not to stick out in the blockchain.

Can somebody provide default options for various transactions on current versions of Bitcoin Core and Electrum?

Options to check are version, locktime, sequence (for every input, with or w/o RBF).

Let's start with most common ones.
legacy:
1) p2pkh > p2pkh
1) p2pkh > p2wpkh
1) p2pkh > p2sh/p2wsh

segwit:
1) p2wpkh > p2pkh
1) p2wpkh > p2wpkh
1) p2wpkh > p2sh/p2wsh

Could somebody explain how vouchers work?
If I send 0.55 BTC and get a voucher, how and when it can be used?

Can it be used in any other session?
Is it valid only while the initial session (7 days) valid?

Are you sure USD cards are available in EU program?

AFAIK you don't need to download this if you run a node
on any bitcoind node you can run dumptxoutset command and then just parse it

and when https://github.com/bitcoin/bitcoin/pull/18689/ gets merged, you won't even need to parse it

iMil
Do you have any plans for Goxplorer to use new dumptxoutset rpc functionality https://github.com/bitcoin/bitcoin/pull/16899?
So the user doesn't have to scan block files and use copies/overlay.

Please explain what will happen in this situation.

1) I send 2.049 BTC to ChipMixer and choose to get a a voucher.
What kind of voucher(s) I get? Is it one for 2.049 BTC or two for 2.048 BTC + 0.001 BTC?
2) Another mix, I send 2.048 BTC, also choose to get a voucher.
What kind of voucher(s) I get?
3) I want to sweep my vouchers. So I submit all of them from steps 1&2, what are my options now?
Can I specify what kind of chips I want to get? Can I choose 4.096 BTC chip now? Do I have to completely spend the whole value I have in vouchers right now (can I keep 0.001 BTC for the future mix in voucher form)?
Can I choose to make ChipMixer send me the whole 4.097 BTC to my single address in 1 tx (note, it's not a size of a chip)?
Can I choose ChipMixer to give me 1.024 BTC chip privkey? What will happen to the remainder value (3.073) in vouchers? Will I get new vouchers?
4) If I choose to make ChipMixer send me the value I want, what fee do they use?


PS How big is ChipMixer's pool? If I want to mix 100 BTCs in a month will I start getting my own BTC in a week or will they all be not the ones I deposited?