Numbered titles sort by numeric value: “Page 2” < “Page 10”. A dot is plain text, so “Vol 1.5” < “Vol 1.10”, matching Explorer/Finder. The comparator is a total order, so pagination boundaries stay deterministic.
The sort locale follows server.sort-locale / KOMGA_SORT_LOCALE (BCP47, e.g. zh-CN for pinyin order). Page order and series book numbering use the same comparator.
The Java version hard-codes the UCA root and sorts numbered titles lexicographically (“Page 10” < “Page 2”).