Is libre Twain compliant I wish to scan to a text file
TWAIN is a standard for communication with scanners; it’s scanners that may be TWAIN-compliant or not. LibreOffice on Windows supports TWAIN. Note that only version 6.3 (and later) of 64-bit LibreOffice for Windows support TWAIN.
However, TWAIN has nothing with scanning to a text file: this is a totally independent task of OCR. LibreOffice does not have in-built OCR functionality, and only imports images taken from scanners as images. You would need a dedicated software to convert scans to text.