Less than most engineering teams expect. Extracts and summaries establishing that the process exists, that the applicant worked on it, and that the receiving site needs it are usually more effective than complete technical packages, which are hard to review and hard to clear for release.
Prefer signed statements over dumped attachments
A short statement from an engineering manager describing the process at a controlled level of detail, with the applicant's specific contributions and dates, does more work than a folder of drawings. Where a document must be referenced but not disclosed, note its title, date, and custodian. Keep a private index of what was withheld and why, so later questions can be answered without reopening the disclosure decision from scratch.
Decide the size of the file by what a reader can absorb in an hour. A process summary of two pages, a manager statement of two pages, and an annotated list of internal documents with titles, revision numbers, and custodians usually outperform a technical package nobody outside the plant can follow. Keep a private index of what was withheld and why, held by a named person, so a later request can be answered consistently.
Where work instructions were produced in another language, arrange certified translations of the extracts actually relied on rather than of the whole document set. Check that every date in the file agrees with the personnel record, because a single mismatched year draws attention to everything else.