Have you ever gone to sea or been on a ship?

The first seven flags are definitely letters, only the last one belongs to a country

Look at the URL

extrem spoiler

What is located at the address. You have seen the small corner, top right of the graphic, with an arrow pointing to it.

There is nothing to interpret here,

Calm down, count to ten

Finally, I have found the solution.
I just had to sleep on it one night.
The logic behind the puzzle is as suspected, but you do not need any existing transformation table from a previous puzzle.