Here’s another installment.

Koha

Export
Built in. Can export/dump Marc, MODS and DC.
Database Access
Built in. Multiple databases are supported such as MySQL, Postgres and Oracle. The tables are documented.
API's and Web Services
Built in. SRW/SRU and Z39.50 are offered. OpenSearch is also built in.

There is now a resource sharing site available to assist in the sharing of library built tools that work with koha. Data access utilities may be included.