Use when building a custom, one-off migration that pulls content from an external source — a headless CMS export, legacy database, CSV/JSON dump, scraped archive, or another WordPress site — into WordPress. Covers profiling the source data, mapping it onto post types/taxonomies/meta/users, writing an idempotent resumable import script, WP_IMPORTING and side-effect suppression, dry runs, throttling, media handling, the production run, and post-import verification.
