Text-Base format with the file extension ".TBs" includes full version of document text. All document components are still in a raw original form.
The purpose of the format is to handle large quantity of documents in a data-base kind of format which allows operations like add, delete and update of records in a form of documents. Next to the simple storage, the format allows indexing of the documents.
The format doesn't store the documents in a single file but includes many files, all with the same base file name but with the different suffix.