While working on MDL-77708, I found the following pages that are referenced in Moodle LMS code and still need to be migrated. 

I've tried to classify them, in order to make it easier to migrate them to https://moodledev.io/ 

PROJECTS

https://docs.moodle.org/dev/Admin_tools

https://docs.moodle.org/dev/Lightwork

https://docs.moodle.org/dev/Events_API

https://docs.moodle.org/dev/Output_renderers#Theme_renderers

https://docs.moodle.org/dev/Backup_1.9_conversion_for_developers

https://docs.moodle.org/dev/General_report_plugins

APIs

https://docs.moodle.org/dev/lib/formslib.php_Form_Definition → Include missing information in the proper pages in https://moodledev.io/docs/apis/subsystems/form

https://docs.moodle.org/dev/Inplace_editable

https://docs.moodle.org/dev/Filter_enable/disable_by_context → https://moodledev.io/docs/apis/plugintypes/filter

https://docs.moodle.org/dev/Adding_a_Portfolio_Button_to_a_page → https://docs.moodle.org/dev/Portfolio_API

http://docs.moodle.org/dev/Writing_a_Portfolio_Plugin → https://docs.moodle.org/dev/Portfolio_API

https://docs.moodle.org/dev/Modal_and_AJAX_forms → https://moodledev.io/docs/apis/subsystems/form/advanced/

http://docs.moodle.org/dev/Message_API

http://docs.moodle.org/dev/Errors_handling_in_web_services → https://moodledev.io/docs/apis/subsystems/external

https://docs.moodle.org/dev/Implementing_Course_drag_and_drop_upload_support_in_a_module

https://docs.moodle.org/dev/Comment_API

https://docs.moodle.org/dev/Rating_API

http://docs.moodle.org/dev/Quiz_access_rules  → https://docs.moodle.org/dev/Quiz

https://docs.moodle.org/dev/Workshop

https://docs.moodle.org/dev/Question_Engine_2

http://docs.moodle.org/dev/Creating_a_web_service_client → https://moodledev.io/docs/apis/subsystems/external

https://docs.moodle.org/dev/Themes

https://docs.moodle.org/dev/Boost_Presets 

MIGRATE or NOT MIGRATE

https://docs.moodle.org/dev/Migrating_logging_calls_in_plugins (Moodle 2.7)

http://docs.moodle.org/dev/Migrating_log_access_in_reports (Moodle 2.7)

It would be great to prioritise them and, once migrated, create another issue in the tracker to replace the missing links to docs.moodle.org/dev.