Under the auspices of OASIS appears a discussion document about the ‘search web service’.
The Search web service is a means of opening a database to external enquiry in a standardized manner that facilitates discovery of query and response possibilities and makes it possible for heterogeneous databases to be queried simultaneously with the same or similar queries. Client software can be easily configured using a standardized XML explain document that is accessible from the base URL or via the explain operation. In contrast with protocols such as SQL and XQuery, detailed knowledge of a database’s structure is not necessary as the explain document contains parsable information on server defaults, searchable indexes and record schemas that are returned in the response. [OASIS Specification Template]
There is a cryptic note about its relationship to SRU:
This specification is based on the SRU (Search Retrieve via URL) specification which can be found at https://www.loc.gov/standards/sru/. It is expected that this standard, when published, will deviate from SRU. How much it will deviate cannot be predicted at this time. The fact that the SRU spec is used as a starting point for development should not be cause for concern that this might be an effort to fast track SRU. The committee hopes to preserve the useful features of SRU, but not to preserve those that are not considered useful. [OASIS Specification Template]