When reviewing apps to accept, F-Droid takes the user’s point of view, first and foremost. We start with strict acceptance criteria based on the principles of free software and user control. There are some things about an app that might not block it from inclusion, but many users might not want to accept them. For these kinds of things, F-Droid has a defined set of Anti-Features. Apps can then be marked with these Anti-Features so users can clearly choose whether the app is still acceptable.

Anti-Features are organized into “flags” that packagers can use to mark apps, warning of possibly undesirable behaviour from the user’s perspective, often serving the interest of the developer or a third party. Free software packages do not exist in a bubble. For one piece of software to be useful, it usually has to integrate with some other software. Therefore, users that want free software also want to know if an app depends on or promotes any proprietary software. Sometimes, there are concepts in Anti-Features that overlap with tactics used by third parties against users. F-Droid always marks Anti-Features from the user’s point of view. For example, NSFW might be construed as similar to a censor’s blocklists, but in our case, the focus is on the user’s context and keeping the user in control.

You will see our Anti-Features in action when viewing the details of any app containing one or more Anti-Features, whether in the F-Droid client or on this website. The F-Droid client also provides settings to hide apps with certain Anti-Features.

List of Anti-Features

F-Droid currently uses this list of Anti-Features for labeling apps we are shipping:

• Ads - advertising
• Tracking - tracks and/or reports your activity to somewhere, even when it can be turned off
• Non-Free Network Services - promotes or depends entirely on a non-changeable or non-free network service
• Non-Free Addons - promotes other non-libre apps or plugins
• Non-Free Dependencies - needs a non-libre app to work (e.g. Google Maps, Market)
• NSFW - contains content that the user may not want to be publicized or visible everywhere
• Upstream Non-Free - upstream source code is not libre, and this version has those parts replaced or rewritten
• Non-Free Assets - non-libre media in things that are not code (e.g. images, sound, music, 3D-models, or video)
• Known Vulnerability - known security vulnerability
• Disabled Algorithm - signed using an unsafe algorithm
• No Source Since - source code no longer available, making new releases impossible

Here’s a complete list of all apps in F-Droid containing Anti-Features.

Ads

This Anti-Feature is applied to an app that contains advertising.

Note that most applications that contain advertising are not Free Software, because they use proprietary software (e.g. AdMob) to provide that advertising. Those apps will not be found in the repo at all, so the only time you would see this Anti-Feature applied would be an app that contains advertising without using Non-Free Software to do it.

Here’s the list of apps with Ads.

NSFW

This Anti-Feature is applied to an app that contains content that the user may not want to be publicized or visible everywhere. The marked app may contain nudity, profanity, slurs, violence, intense sexuality, political incorrectness, or other potentially disturbing subject matter. This is especially relevant in environments like workplaces, schools, religious and family settings. The name comes from the Internet term “Not safe for work”.

Here’s the list of apps with NSFW.

Tracking

This Anti-Feature is applied to apps that track you and/or report your activity to somewhere, either without your permission or by default (i.e. you’d have to actively seek out an option to disable it).

Examples of where this Anti-Feature might be applied:

• Sending crash reports without your knowledge or permission
• Checking for updates without your knowledge or permission

Examples of where it would not be applied - any of the above, if the functionality is opt-in (i.e. you are asked before it happens) and disabled by default. Enabling it should then also require informed consent, i.e. requiring a privacy policy similar to GDPR, and avoid collecting personal data (PII) as far as possible.

Note that frequently app tracking is implemented using proprietary software, e.g. Google Analytics or Flurry. Apps containing these proprietary libraries will not be found in the F-Droid repo.

Here’s the list of apps with Tracking.

Non-Free Network Services

This Anti-Feature is applied to apps that promote or depend entirely on a Non-Free network service, or any service which is impossible, or not easy to replace. Replacement requires changes to the app or service. This antifeature would not apply, if there is a simple configuration option that allows pointing the app to a running instance of an alternative, publicly available, self-hostable, free software server solution.

Here’s the list of apps with Non-Free Network Services.

Non-Free Addons

This Anti-Feature is applied to apps that, although Free Software themselves, promote other Non-Free applications or plugins.

Here’s the list of apps with Non-Free Addons.

Non-Free Dependencies

This Anti-Feature is applied to apps that require things that are not Free Software in order to run.

This does not mean that proprietary software is included in the app, but for example, it may depend on other software already being installed on your device. A common example would be an app that doesn’t run, or is not useful, unless you have Google Maps installed.

Here’s the list of apps with Non-Free Dependencies.

Upstream Non-Free

This Anti-Feature is applied to apps where the upstream source code includes proprietary software by default in their own releases.

This does not mean that proprietary software is included in the app. Most likely, the F-Droid build has been patched in some way to remove the Non-Free code/libraries, and/or some functionality may be missing. The app’s description will usually go into more detail about this.

In our experience, where the upstream developer includes Non-Free libraries, sooner or later they will include more Non-Free libraries, or other Anti-Features. Frequently they become impossible to maintain/update in F-Droid. If there is an alternative, it is recommended that you avoid applications with this Anti-Feature if future updates are important to you.

Here’s the list of apps with Upstream Non-Free.

Non-Free Assets

This Anti-Feature is applied to apps that contain and make use of Non-Free assets. The most common case is apps using artwork - images, sounds, music, etc. - under a license that restricts commercial usage or making derivative works (for example, any Creative Commons license with a “Non-Commercial” (NC) or “No Derivatives” (ND) restriction).

Here’s the list of apps with Non-Free Assets.

Known Vulnerability

This Anti-Feature is applied to apps with a known security vulnerability, found by one of the scanners in fdroidserver.

Here’s the list of apps with Known Vulnerabilities.

Disabled Algorithm

This Anti-Feature is applied to apps that were signed using a signature algorithm that is considered outdated or unsafe.

Here’s the list of apps signed with Disabled Algorithms.

No Source Since

The upstream source for this app is no longer available. Either the app went proprietary, the source repository was dropped, or it has moved to a location currently not known to us. This means there will not be further updates unless the source reappears.

Here’s a list of apps with No Source.

Reporting Anti-Features

While our package maintainers are working hard to find all Anti-Features and bring them to your attention, some might remain unnoticed or slip in with an app update. Should you discover that an app contains an Anti-Feature F-Droid is not aware of, please report it. You can submit them by E-Mail to team@f-droid.org or open an issue here: gitlab.com/fdroid/fdroiddata/issues.

Origins of the F-Droid definition of Anti-Features

The Free Software Foundation (FSF) also has a similar idea, and it is also known as “anti-features”. “Anti-features are sold to customers as features but are fundamental or unavoidable aspects of systems that can only be removed or withheld through technological effort”. Another way of thinking about Anti-Features is that they are “functionality that a technology developer will charge users to not include”. The F-Droid definition was initially inspired by FSF’s, but our definition has evolved over the years into something different.