Apply suggestions from code review

Co-authored-by: Rod Vagg <[email protected]>

Author: hanabi1224

FRCs/frc-0108.md

@@ -60,9 +60,10 @@ We propose the below changes to the [V1 Filecoin CAR snapshot format](#v1-specif
 
 ```go
 type SnapshotMetadata {
-	Version       uint64 // required, format version for SnapshotMetadata. Only "2" is supported since "v1" was implied in the original format that predates `SnapshotMetadata`.
-	HeadTipsetKey []Cid // required
-	F3Data        *Cid  // optional, points to F3Data structure. The only supported codec is "RAW" (0x55).
+	Version       uint64 // Required, format version for SnapshotMetadata.
+	                     // Only "2" is supported since "v1" was implied in the original format that predates `SnapshotMetadata`.
+	HeadTipsetKey []Cid  // Required
+	F3Data        *Cid   // Optional, points to F3Data structure. The only supported codec is "RAW" (0x55).
 }
 ```
 
@@ -231,9 +232,13 @@ Node users should experience faster F3 bootstrapping time and less network bandw
 ## Product Considerations
 <!--All FIPs must contain a section that discusses the product implications/considerations relative to the proposed change. Include information that might be important for product discussion. A discussion on how the proposed change will enable better storage-related goods and services to be developed on Filecoin. FIP submissions missing the "Product Considerations" section will be rejected. An FIP cannot proceed to status "Final" without a Product Considerations discussion deemed sufficient by the reviewers.-->
 
-Nodes starting from a snapshot should not rely on the certificate exchange protocol to catch up with the F3 data because we expect this will get slower over time. A slow F3 catchup time leads to, e.g.
+### Start-up without initial F3 data
 
-- delay in the readiness of F3-aware RPC APIs
+Nodes starting from a snapshot should not rely on the certificate exchange protocol to catch up with the F3 data because we expect this will get slower over time. One outcome of a slow F3 catchup time is a delay in the readiness of F3-aware RPC APIs.
+
+### CAR format expectations
+
+This change introduces a relatively novel use of the CAR format in that it contains one very large block, much larger than typical blocks found in most CAR containers for use with IPLD data. At the time of this proposal, this block size would be approximately TODO MiB and this will only grow over time. While this is not disallowed by the CAR specification, many CAR processing utilities are built on an assumption of classic IPFS style blocks of more more than approximately 1MiB each. Some CAR tooling may struggle to deal with the new proposed format, although handling CAR data outside of the narrow use-case of snapshort imports on Filecoin nodes is not typical or necessarily recommended.
 
 ## Implementation
 <!--The implementations must be completed before any core FIP is given status "Final", but it need not be completed before the FIP is accepted. While there is merit to the approach of reaching consensus on the specification and rationale before writing code, the principle of "rough consensus and running code" is still useful when it comes to resolving many discussions of API details.-->