I believe this is "PDSERF stands for Political Disclosure Standard Electronic Reporting Format" a format used by [SDR Technologies]
As for the file format, I found this about it
This format utilizes EDI, the Electronic Data Interchange, standards developed and maintained by the Accredited Standards Committee X.12 of the American National Standards Institute."
You can tie this into Texas in this proposal by the Texas Ethics Commission which was later subsequently rewarded
On January 11, 2000 I attended a public briefing in the Capitol Extension held by the Texas Ethics Commission and SDR Technologies, Inc. to discuss specifications for a standard file format for filing reports electronically with the Ethics Commission. This file format will be available to commercial vendors so they may generate campaign finance reports for filing electronically from their software. Additionally, the briefing demonstrated how filers will be able to convert data from spreadsheets such as Excel or Access for filing campaign finance reports electronically. On February 16, 2000 I attended another similar public briefing, which included a filer software demo.
You can also see them talk about it here,
The document produced by SDR Technologies describing the filing format used for electronically submitting disclosure and registration documents to the Texas Ethics Commission (i.e., containing the technical specifications) is available upon request. It is located in the appraisal files of the Archives and Information Services Division of the Texas State Library and Archives Commission, and is titled "Texas PDSERF/Plus (.PDP) File Layouts."
I think the PDSERF/Plus is an SDR Technologies thing. They also seem to service the Federal Election Commission. You can see them pitch their product to the State of California here, and Michagan, and Louisiana also seem to use it (or have used it).