By default, Sitecore uses a built-in, hard coded, SchemaPopulateHelper class that handles updates of the Solr Managed schema. When changes are needed to the schema, a lot of code needs to be overridden and things becomes pretty complex to handle.
This module replaces the built in SchemaPopulateHelper and allows writing the Solr schema as plain XML within the Sitecore config system. This allows using the Sitecore config patch system. It also allows cleaner configuration, as the Sitecore index configuration field mapping, document options etc can be placed together with corresponding schema changes where applicable.
The module is written for Sitecore 9.3, but can easily be adjusted to work with previous versions. Note that the ISchemaPopulateHelper inteface is slightly different in earlier versions, but the concept is the same since Sitecore 9.0.