[JarryShaw]

• Searched for similar pull requests
• Followed the coding style
• make test passes, and a test case covers the change
• Changelog entry: N/A — centralised in docs(changelog): shared 1.5.0 changelog — long-lived, merges last (#610, #616, #617, #618, #620) #657

What is the purpose of your pull request?

• fix — bug fix

---

Description

Closes #2295.

• Problem: _read_opt_sec warns when the final protection-authority octet has its low-order bit (the RFC 1108 field termination indicator) set, but the message said the indicator was "not set" — backwards from what was observed.
• Fix: describe the observed bit and its value, e.g. field termination indicator set on the final octet: 145.
• Test: test_sec_termination_indicator_follows_rfc_1108 pins the exact message for SEC option 8204ab91.

[JarryShaw]

Review: GOOD TO GO at d5273f866 (Sonnet). Confirmed with real RFC 1108 SEC option bytes: on origin/main the warning said "not set" while the parsed model said the bit WAS set (backwards); on the PR head it correctly reports field termination indicator set on the final octet: 145. Six option-byte variants checked, RFC 1108 §2.4(a) read directly, unaffected paths (bit clear, non-final octet) unchanged. New test fails without the fix (confirmed). Clean merge onto current main, 97 tests + 588 subtests pass merged.

Ready to merge.
CI: 32 success / 7 skipped / 0 failed at review time, rest still queued.
Mergeable, 0 unresolved threads.

[JarryShaw]

Correction: "Ready to merge" above was premature — CI still has 13 checks not yet complete (pending/queued). Review verdict stands (GOOD TO GO), but holding the ready call until CI actually finishes.

[github-actions]

Coverage: 91.58% (unit tier, Python 3.15, d5273f866, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	4	20	2	95.16%
pcapkit/const	19601	881	2620	867	92.12%
pcapkit/corekit	2596	74	818	37	96.51%
pcapkit/dumpkit	282	3	102	3	98.44%
pcapkit/foundation	3029	23	1050	25	98.82%
pcapkit/interface	138	4	52	3	96.32%
pcapkit/protocols	17455	218	4598	185	98.15%
pcapkit/toolkit	914	36	334	10	95.51%
pcapkit/utilities	502	7	144	5	98.14%
pcapkit/vendor	4432	1988	1018	167	51.87%

Per-file detail: the coverage-html artifact of this run.

[JarryShaw]

Ready to merge — confirming this time with the full check state.

Review: GOOD TO GO (Sonnet) at d5273f866.
CI: Required checks passed, 0 failures (only the non-blocking experimental GraalPy leg still pending).
Mergeable, 0 unresolved threads.