I found an article in knowledge base stating that search score is affected by document date, occurence of keywords in title, and in body, and also number of links to this document.
https://confluence.atlassian.com/confkb/how-do-i-understand-the-ranking-of-confluence-s-search-results-785614686.html
Does the search engine take in account Confluence specific fields for search results scoring?
such as Number of Likes (could weight the popularity like the links)
or
Number of occurences of searched keyword as page or attachment labels (should have abetter weight than occurences in body)
in addition, how are scored page with macros? as example occurences of search keyword that appear within an "Excerpt" macro could have better score.
How are indexed pages using include macro? does the search indexes the page source or rendered page once macros are executed?