Notandia browser extension

Notandia is an independent, open-source browser extension that adds configurable publisher context and explainable post-publication signals to scholarly literature. It preserves the mature MDPI-detection capabilities previously distributed as MDPI Filter while generalizing them into user-controlled publisher watchlists. This repository is the canonical source for Chrome, Microsoft Edge, Firefox, and Safari.

Independent project: Notandia is not affiliated with, authorized by, or endorsed by MDPI AG, Frontiers Media SA, Crossref, Retraction Watch, NCBI, browser vendors, or any publisher or data provider. Publisher names and marks belong to their respective owners.

Browser outputs

Target	Generated release asset	Distribution status
Chrome	notandia-chrome-vX.Y.Z.zip	Uploadable to the existing Chrome Web Store item
Microsoft Edge	notandia-edge-vX.Y.Z.zip	Uploadable to the existing Microsoft Edge Add-ons product
Firefox	notandia-firefox-source-vX.Y.Z.zip	Submitted to AMO for Mozilla signing
Safari	notandia-safari-source-vX.Y.Z.zip	Local compatibility source; App Store publication deferred

All packages are generated from the same source commit. Browser-specific manifests, store metadata, terminology restrictions, and credentials remain isolated.

Features

Configurable publisher watchlists

• Identify enabled publisher profiles in article pages, reference lists, and supported search-result pages.
• Ship built-in MDPI and Frontiers profiles, both enabled and highlighted by default on fresh installations.
• Distinguish MDPI in amber and Frontiers in violet, with visible publisher names as well as color. Existing saved colors and actions are preserved.
• Allow every publisher profile—including MDPI—to be independently enabled or disabled.
• Apply a per-publisher action: context only, badge, highlight, dim, or hide.
• Configure a separate color and confirmed-only or potential-match policy for each profile.
• Preserve the mature MDPI detector as an additional evidence source for pages where direct publisher domains or DOI prefixes are unavailable.

A watchlist match identifies a publisher selected in the user's settings. It is not a quality score and does not claim that every article from a matched publisher is unreliable.

MDPI preserves the project's original MDPI Filter focus. Frontiers expands the initial scrutiny watchlist. Settings include the selection rationale, dated source review, and links to Finland's classification decision and Norway's journal-by-journal approach. Exceptions, restorations, and differences between assessment systems matter; Notandia does not retrieve current journal classifications or designate these entire publishers as predatory.

Settings provide MDPI and Frontiers controls, manual publisher adding, import/export, Reset defaults, diagnostic logging and Crossref/NCBI checks. Preset catalogues are deferred. Existing saved profiles remain usable and can be removed from Settings. Reference details retain attributed sources, and the overview reports watchlist matches against scanned references when coverage is available.

The optional Additional publisher and journal warnings setting uses the full bundled Cite Unseen publisher and standalone-journal lists: 1,334 publisher URL entries and 1,498 journal URL entries, dated 30 March 2026. Matching runs locally, preserving listed paths and query selectors. Each match links to its source and edition. Saved publisher and manual domain controls take precedence, including disabled choices. Import/export includes the setting. See data attribution and licence.

MDPI detection includes the five DOI prefixes listed by CiteWatch and verified against Crossref; Frontiers detection includes 10.3389 and 10.4175. Preprints.org references carry a Preprint label and platform explanation; recognised Encyclopedia DOI entries carry an Encyclopedia entry label. These labels describe the cited work's type.

For a local presentation, open the synthetic demo. It uses the actual publisher matcher and notice renderer with invented records to demonstrate distinct publisher colors and formal notices outside the initial watchlist. It performs no API requests and makes no claims about real articles. See accessibility validation for checks and limits.

Integrated article and reference context

• Present current-article publisher matches and formal update status together while keeping those concepts independent.
• Combine publisher-profile chips and retraction, correction, concern, withdrawal, duplicate-publication, and reinstatement signals in one reference/result view.
• Scroll from a popup record to its corresponding page reference where the page structure permits.
• Use structured issue-report categories for missed or incorrect publisher context, integrity status, confidence, layout, and suggested presets.

Research-integrity metadata

• Optionally check the current article and DOI-bearing references for formal Crossref/Retraction Watch update relationships.
• Query both a work's direct Crossref metadata and reverse updates:<doi> relationships so separately registered notices can be found.
• Show evidence type, chronology, provenance, coverage, deferred checks, and unresolved checks instead of producing an opaque quality score.
• Offer a prominent first-use prompt to enable recommended Crossref and NCBI checks together. Both remain off until enabled, can be controlled independently, and a choice to keep current settings is remembered on the device.

Defaults and migration

Fresh installations begin with:

Profile	Enabled	Action
MDPI	Yes	Highlight
Frontiers	Yes	Highlight

Both settings are user-controlled. Published MDPI Filter installations are migrated into the versioned watchlist schema. The legacy MDPI mode, potential-match preference, and color are preserved rather than overwritten by the new defaults.

Identity and update compatibility

Notandia is a public-facing rebrand and expansion of released Chrome and Microsoft Edge software, not a replacement extension.

• Chrome keeps its existing extension ID and registered CRX signing key.
• Microsoft Edge keeps its existing Product ID and extension identity.
• Firefox has not been released; its first release uses Gecko ID browser-extension@notandia.github.io.
• Existing storage keys and MDPI-specific runtime identifiers remain temporarily where changing them could reset published-user settings or break compatibility.
• New release files, store-facing metadata, UI labels, documentation, and public project links use Notandia.

These legacy identifiers are compatibility mechanisms, not current product branding. See Identity compatibility.

Development

Requirements:

• Node.js 24
• npm
• zip for creating release archives locally

Run the complete verification and build:

npm ci --ignore-scripts
npm test
npm run build

Generated unpacked extensions appear under:

dist/chrome
dist/edge
dist/firefox
dist/safari

Build one target:

npm run build:target -- --target edge --version 0.1.0

Releases

A protected version tag such as v0.1.0 triggers the multi-browser release workflow. It:

1. Runs the security and regression suite.
2. Builds all browser targets independently.
3. Enforces store-specific terminology policies.
4. Creates reproducible ZIP archives.
5. Verifies each archive and manifest.
6. Publishes one GitHub release with all four packages and checksums.txt.

Store publication is intentionally separate from package creation. The Publish Browser Store workflow downloads the already verified release asset, checks its SHA-256 hash, and then uploads or submits it through the official store mechanism behind a protected GitHub Environment.

See Multi-browser releases and store publication for the exact account, secret, environment, and migration setup.

Local installation

Chrome

1. Build the Chrome target.
2. Open chrome://extensions.
3. Enable Developer mode.
4. Select Load unpacked and choose dist/chrome.

Microsoft Edge

1. Build the Edge target.
2. Open edge://extensions.
3. Enable Developer mode.
4. Select Load unpacked and choose dist/edge.

Firefox

1. Build the Firefox target.
2. Open about:debugging.
3. Select This Firefox → Load Temporary Add-on.
4. Select dist/firefox/manifest.json.

Ordinary permanent installation requires Mozilla signing.

Safari

Build the Safari target and use Safari's temporary web-extension development flow. The generated source package is not an App Store-signed application.

Security and privacy

The extension:

• Uses Manifest V3 or the browser's compatible Web Extension form.
• Requests only storage as a standard extension permission.
• Executes no remote code.
• Includes no runtime npm dependencies.
• Stores publisher profiles locally through browser extension storage.
• Keeps Crossref integrity lookups off until the user explicitly enables them.
• Sends only bounded scholarly identifiers to documented APIs.
• Limits an integrity scan to 50 unique DOI requests and no more than four request starts per second.
• Cancels active and queued integrity requests when disabled, replaced by a newer scan, or navigation begins.
• Omits browser credentials and referrer information from NCBI and Crossref requests.
• Does not send complete page text, citation text, full URLs, search queries, browsing history, enabled publisher-profile data, account identifiers, or analytics identifiers to Crossref.
• Supports a zero-network configuration.
• Uses pinned GitHub Actions and deterministic release inputs.

See SECURITY.md, PRIVACY.md, and the project website for current disclosures.

Known limitations

Some publisher pages use nonstandard, dynamically loaded, collapsed, or author-year citation structures. Reference-list detection can work even when inline-citation marking or scroll-to-reference cannot be performed safely. False-positive avoidance takes priority over guessing from weak journal-title evidence.

Publisher matching relies on configured domain, DOI-prefix, and mature legacy-MDPI evidence. A match is contextual metadata selected by the user, not a statement about an article's validity.

Integrity coverage depends on DOI availability and the formal relationships present in checked Crossref records. A result saying no known signal was found is not a guarantee that a work is correct or reliable. Deferred, failed, and unresolved checks are not treated as clear.

Representative regression pages include PubMed Central, Europe PMC, Nature, Frontiers, MDPI, Cell, BMJ, ScienceDirect, Wiley, Sage, Taylor & Francis, Oxford Academic, LWW, and Wikipedia pages. Regressions should be filed with the sanitized page URL, browser/version, extension version, expected result, and actual result.

License

• Code: GNU AGPL-3.0-or-later
• Logo: CC BY-SA 4.0

The same optional warning group includes Wikipedia CiteWatch’s publisher and journal configurations (1,381 and 2,122 records). It matches additional DOI prefixes and structured journal/publisher metadata locally. Explanations include dated sources and assessment notes. Ambiguous names, shared prefixes and journal-specific exceptions restrict matching; these signals are marked as potential. See bundled source coverage.