Many of "DocBook XSL Stylesheets V1.79.1" based documentation refers to pdf documentation.
For example https://www.boost.org/doc/libs/1_82_0/libs/type_traits/doc/html/index.html

While last update of such documentation was in v1.56.0 2014-08-14

Maybe it worth to find all such mentions and remove them if pdf documentation is no longer provided.
Many of "DocBook XSL Stylesheets V1.79.1" based documentation refers to pdf documentation.
For example https://www.boost.org/doc/libs/1_82_0/libs/type_traits/doc/html/index.html

While last update of such documentation was in v1.56.0 2014-08-14

Maybe it worth to find all such mentions and remove them if pdf documentation is no longer provided.