diff --git a/ROADMAP.md b/ROADMAP.md
index 796ff7306..8443ae9e6 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -388,6 +388,7 @@ list) · [roadmap.md](docs/roadmap.md) (milestones, plan) · [parity-checklist.m
 
 Newest first.
 
+- **2026-10-31** · A `.designcraft` file opened from bytes (`file.openBytes` with its file name, as a browser or host passes it) is titled without the extension, as an IDML file opened that way is. Saving it in the browser downloaded `Brochure.designcraft.designcraft`, and the File Name variable showed the doubled name. No readiness percentage change.
 - **2026-10-30** · Import warnings about a story have a Show button: it closes the warnings (the status line keeps them) and selects the story's first frame, fitted in the window. `file.open` returns `warningItems`, the frame each IDML or InDesign warning is about (or null), matching the converter's INDD story numbers (`story 30892`, written to IDML as `u78ac`) and IDML `Self` names to the imported stories. No readiness percentage change.
 - **2026-10-30** · Parent pages: a running-header variable shows its name in angle brackets on the parent itself (it was blank), as InDesign shows it; on the document pages, and in text with no page, it shows its text as before. No readiness percentage change.
 - **2026-10-30** · Without facing pages, a page of a multi-page spread shows the parent page in its place, as in InDesign: the second page of a two-page spread shows the parent's second page. Every single-sided page showed the parent's first page, so an InDesign book set up without facing pages but laid out in two-page spreads repeated the left parent page's items (a black heading bar) on its right pages and lost the right parent page's. No readiness percentage change.
diff --git a/crates/engine/src/cmd/file/bytes.rs b/crates/engine/src/cmd/file/bytes.rs
index 0946205a8..f42925034 100644
--- a/crates/engine/src/cmd/file/bytes.rs
+++ b/crates/engine/src/cmd/file/bytes.rs
@@ -27,6 +27,16 @@ pub fn with_document_extension(path: &str) -> String {
     format!("{path}.{}", designcraft_format::EXTENSION)
 }
 
+/// `name` without a trailing `.designcraft` (any case): the title of a document opened from bytes
+/// under its file name. Save, Save As and the File Name variable add the extension back, so a title
+/// that kept it would name the file `Brochure.designcraft.designcraft`. A bare `.designcraft` stays.
+pub(super) fn without_native_extension(name: &str) -> &str {
+    match name.rsplit_once('.') {
+        Some((stem, ext)) if !stem.is_empty() && ext.eq_ignore_ascii_case(designcraft_format::EXTENSION) => stem,
+        _ => name,
+    }
+}
+
 /// Whether `bytes` are a document `file.open` reads: a DesignCraft package or an IDML package.
 /// The first [`DOCUMENT_SNIFF_BYTES`] of a file are enough for packages that start with their
 /// `mimetype` entry, as both formats write them.
diff --git a/crates/engine/src/cmd/file/open.rs b/crates/engine/src/cmd/file/open.rs
index 75a7ce627..01d268635 100644
--- a/crates/engine/src/cmd/file/open.rs
+++ b/crates/engine/src/cmd/file/open.rs
@@ -1,6 +1,6 @@
 #[cfg(test)]
 use super::bytes::{PREVIEW_PX, to_bytes};
-use super::bytes::{base64_decode, load_bytes};
+use super::bytes::{base64_decode, load_bytes, without_native_extension};
 use super::{Arc, DocState, Document, EngineError, Result, Session, Value, bad, json, str_param};
 
 pub(super) fn has_recent(s: &Session) -> std::result::Result<(), String> {
@@ -150,7 +150,8 @@ pub(super) fn file_open_bytes(s: &mut Session, p: &Value) -> Result<Value> {
     let (mut d, warnings) = load_bytes(&b)?;
     crate::cmd::datamerge::resolve_sources_on_open(&mut d, None);
     if let Some(n) = str_param(p, "name") {
-        d.title = n.to_string();
+        // Titled as an IDML file opened from bytes is: without its extension.
+        d.title = without_native_extension(n).to_string();
     }
     let i = s.add_document(DocState::new(d, None));
     Ok(json!({"index": i, "warnings": warnings}))
@@ -413,6 +414,35 @@ mod document_fonts_tests {
     }
 }
 
+#[cfg(test)]
+mod open_bytes_tests {
+    use serde_json::json;
+
+    use crate::Session;
+
+    /// A `.designcraft` file opened from bytes under its file name (a browser or host passes the
+    /// name it has) is titled without the extension, as an IDML file is, so saving it gives
+    /// `Brochure.designcraft` and not `Brochure.designcraft.designcraft`.
+    #[test]
+    fn open_bytes_titles_a_native_document_without_its_extension() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({})).unwrap();
+        let native = s.execute("file.serialize", &json!({})).unwrap();
+        for (name, title) in [
+            ("Brochure.designcraft", "Brochure"),
+            ("Brochure.DesignCraft", "Brochure"),
+            ("Brochure", "Brochure"),
+            ("Brochure.v2", "Brochure.v2"),
+            ("Brochure.designcraft.designcraft", "Brochure.designcraft"),
+            (".designcraft", ".designcraft"),
+        ] {
+            let r = s.execute("file.openBytes", &json!({"name": name, "base64": native["base64"]})).unwrap();
+            let st = &s.documents()[r["index"].as_u64().unwrap() as usize];
+            assert_eq!((st.doc.title.as_str(), st.title()), (title, title.to_string()), "{name}");
+        }
+    }
+}
+
 #[cfg(test)]
 mod recent_tests {
     use serde_json::json;