Section translation identifies sections potentially missing across two language versions of an article. This is done to encourage users to translate missing sections. In addition, this information can be considered to filter suggestions.
Currently, the mapping approach is based on previous translations made by Content Translation, which has some limitations. We plan to support a combined approach where multiple strategies are used to identify mapping sections in a reliable and effective way. Tickets exploring different approaches are created as sub-tasks of this epic ticket.
Examples of issues with section mapping are compiled in T283817: Compile examples of section mapping issues to use as a benchmark for future improvements