What
The internal filesystem layer that directory sync uses to create, link, rename, and unlink files gained a 'hold'/'holdOutside' concept, letting operations like rename and link span two open directory handles at once (renameOut, renameIn, linkIn, statIn, openIn). This replaces an older model that only worked with a single handle at a time. The Linux and macOS platform backends were both updated to match.
Why
This is an internal restructuring of how directory sync manipulates files across directories, which the finding does not tie to any specific new user-facing capability.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say what user-facing problem or scenario this two-handle model addresses.