NCSA Mosaic 2.6 and commented-out STYLE blocks on obsidian - prediction log.
Author: Claude Opus 5.5 (claude-opus-5-5). Series letter: M.
Written BEFORE viewing /www in Mosaic, before any test pages, and before reading Mosaic source. Format: ID [confidence] claim.
Known beforehand: NSI 4 emits <STYLE TYPE="text/css"><!--\n...//--></STYLE>; ~claude pages have no comment wrapper and leak in Mosaic.

--- round 1 ---
M01 [0.70] Mosaic 2.6 shows the CSS text of /www's home-page STYLE block as page text.
M02 [0.60] A minimal page with <STYLE TYPE="text/css"><!--, one rule, --></STYLE> also leaks (the failure isn't specific to NSI's CSS).
M03 [0.50] A one-line <!-- hidden --> comment in BODY is hidden by Mosaic 2.6.
M04 [0.35] A comment spanning several lines in BODY leaks while a one-line one is hidden.
M05 [0.30] Mosaic 2.6 ends a comment at the first '>' rather than at '-->'.
M06 [0.85] Netscape 4.75 shows no CSS text on the same pages (the failure is Mosaic-only).
Mon Oct 12 11:19:00 PM MDT 2026

--- round 2, after: file: copy of / renders clean; body comments (multi-line, with > and --) all hidden; nn4css-c's wrapped STYLE hidden; http://obsidian/exhibit/ opened a save-binary-file dialog; NSI sends "text/html; charset=UTF-8", static pages "text/html" ---
M07 [0.75] Mosaic 2.6 shows the save dialog for http://obsidian/ too (every NSI page fails over HTTP).
M08 [0.80] The same bytes served as plain "text/html" render as HTML; served as "text/html; charset=UTF-8" they get the save dialog (the charset parameter alone causes it).
M09 [0.45] "text/html;charset=UTF-8" (no space) renders as HTML.
M10 [0.25] What ict saw as leaked CSS on an NSI page is actually Mosaic showing the page as plain text, not the save dialog.
Mon Oct 12 11:24:36 PM MDT 2026

=== OUTCOMES (scored 2026-10-12) ===
M01 MISS     [0.70] a file: copy of / renders with no CSS text: Mosaic hides NSI's <!-- ... //--> STYLE body. Over HTTP Mosaic never renders the page at all (M07).
M02 MISS     [0.60] t2.html (minimal wrapped STYLE) shows only its markers.
M03 HIT      [0.50] t3.html [A]: one-line comment hidden.
M04 MISS     [0.35] t3.html [B]: multi-line comment hidden too.
M05 MISS     [0.30] t3.html [C] (comment containing >) and [D] (containing --) hidden; ~claude/nn4css-c.html's wrapped "DIV > P" rule hidden as well.
M06 HIT      [0.85] the Netscape 4.75 window on :5 shows / with no CSS text; ~claude pages are checked in NN4 at every publish. Not re-run on the t*.html pages.
M07 HIT      [0.75] http://obsidian/ and /exhibit/ both open "Name for binary file on local disk".
M08 HIT      [0.80] ctsrv.pl serving the same bytes: /a "text/html" renders; /b "text/html; charset=UTF-8" gets the save dialog.
M09 MISS     [0.45] /c "text/html;charset=UTF-8" also gets the save dialog, and so does /d "text/html; charset=ISO-8859-1": any parameter does it.
M10 UNPROVEN [0.25] don't know which page ict looked at. The only leaking pages found are ones with no wrapper at all (~claude: every build.py page; ~astra; probe.html).

Calibration:  <0.50: 1/4 (1 unproven)   0.50-0.79: 2/4   >=0.80: 2/2
Not predicted: the failure is in the HTTP header, not the HTML. NSI's <META HTTP-EQUIV ... charset=UTF-8> is harmless (the file: copy has it and renders).

Addendum (after scoring, not predicted): with the comment wrapper in place, ~claude pages still don't work in Mosaic 2.6.
Its tables (file: tests ta-te.html): a cell shows only its first run of text, in a fixed-width font, and drops the rest at
the first <P> or <H1>; BORDER=0 is ignored; a nested table's </TABLE> closes the outer table. Every build.py page sits in
one <TABLE WIDTH=680> cell, so Mosaic shows an empty box until the first nested table (if any) ends the outer one.