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Location: https://www.poe2wiki.net/sitemap/sitemap-poe_wiki-poe2_wiki--NS_0-0.xml
Line Number 18040, Column 1
On to the Hytale Wiki example. I don't know if what I'm about to say applies to Google, but I'm approaching it from the perspective of my tiny dumb indieweb indexer for my personal search engine. It is much easier for me to index from a sitemap rather than try to crawl a website, so I basically look exclusively at sitemaps.
Looking at Hytale Wiki, my process:
* Site has a robots.txt file - good!
* Robots.txt mentions a sitemap - excellent!
* The sitemap is stored at /images/sitemaps/index.xml ... oh. I would usually not index anything from a /images/ folder, because I want to index pages only, not images. This would likely trip my exclusion filters. Let's ignore that and continue.
* The sitemap is a list of an additional 26 nested Gzipped sitemaps. Oh.
This is the point where my tiny dumb indexer would stop. Gzipped sitemaps are part of the standard, but they're relatively rare on the web for small sites. They typically only get used if a sitemap file exceeds the 50,000 pages-per-sitemap limit. In this case, 26 * 50,000 makes the HyTale Wiki look like a 1.3 Million page site. Do I really want to index 1.3 Million pages, an estimated 13GB of indexed text data, about a video game I'll probably never play?
My search index is storage constrained, and my indexer is very time constrained. The time I spend indexing your site is time not spent indexing another, possibly higher quality website. So at this point, I'd just grab the front page and disappear... like Google apparently does too.
Of course, the HyTale site isn't 1.3 Million pages, it's only 4,277 articles. That would all fit in the root sitemap file, and that might be the better approach for getting indexed.