The Write and Edit tool result renderers now use a new streaming file-read approach (ur6() / Pm1()) that reads files through file handles with buffer-based needle search, rather than loading entire files into memory. This improves performance for large file edits by seeking directly to the relevant region.
Evidence
Streaming file read (search for "Skipping raw transcript read: file too large") — Pm1() at line ~317956
Strings lifted out of the shipped bundle, so the claim above can be checked against them.