Six things a document can do once it lives in a repo and what you do without them
the same five lines of spec, in every panel
Diff ON
what changed, by line
1 ## 3.2 Sign-in
2 - Session expires after 60 minutes.
3 - Session expires after 30 minutes.
4 - Three failed attempts lock the account.
5 - SSO is optional for internal users.
6 - Reset sends a one-time link (see 4.1).
What actually changed?
without it “the file has been updated” — a sentence that never says which line
Blame ON
who wrote this line
1 ## 3.2 Sign-in Tanaka
2 - Session expires after 60 minutes. Sato
3 - Three failed attempts lock the account. Sato
4 - SSO is optional for internal users. Suzuki
5 - Reset sends a one-time link (see 4.1). Tanaka
Who wrote this, and when?
without it Ask around, and hope somebody still remembers
Review ON
the argument, on the line
1 ## 3.2 Sign-in
2 - Session expires after 60 minutes.
3 - Three failed attempts lock the account.
4 - SSO is optional for internal users.
5 - Reset sends a one-time link (see 4.1).
why three? two locks people out on a typo — Sato
Why is it written this way?
without it Dig through a chat thread and find the decision without its reason
Revert ON
any past state, one command
1 ## 3.2 Sign-in
2 - Session expires after 60 minutes.
3 - Three failed attempts lock the account.
4 - SSO is optional for internal users.
5 - Reset sends a one-time link (see 4.1).
Can we go back to last Tuesday?
without it Find the previous attachment in an inbox, and hope it is the previous one
Branch ON
a proposal that costs nothing
1 ## 3.2 Sign-in
2 - Session expires after 60 minutes.
3 - Three failed attempts lock the account.
4 - SSO is REQUIRED for internal users.
5 - Contractors keep password sign-in.
6 - Reset sends a one-time link (see 4.1).
Can I propose this without disrupting anyone?
without it Save-as `_proposal.xlsx` — and the truth has one more copy
Gate ON
a document that can fail a check
1 ## 3.2 Sign-in
2 - Session expires after 60 minutes.
3 - Three failed attempts lock the account.
4 - SSO is optional for internal users.
5 - Reset sends a one-time link (see 4.1).
Will anyone notice when it rots?
without it Nobody notices — until someone builds for two weeks against a wrong spec
None of these is a feature of Markdown. They are properties of keeping ONE copy in a place that records every change — which is why the format argument is the small half of this, and the storage argument is the whole of it.