Querying if a URI was visited? Topic is solved

[_yup_]

WRT my initial ideas about the Stargazer implementation - I saw many similar places in the browser sources with (almost) identical SQL query, but was not able to deduce which one is used by nsINavHistoryQuery. The only way to determine this is tracing in the debugger, but if you do not have a complete build environment, you are restricted to Javascript part of code only.

During last three weeks I am trying to revive the Firebug (its debugging part). I compare sources of two Firefox versions (the last one where debugger works and the first one where it does not work) and do not see any significant differences - all relevant parts of code either are identical, or do not have any essential changes.

So I understand what happens between Firebug and browser (or, more closely, what does not happen), but still can not determine why.
And even working debugger does not help.