XCSoar is a powerful tactical glide computer for glider and paraglider pilots.
Free and open-source, with no ads and no tracking.
Runs on Android, iOS, Linux, macOS, and Windows.
Built by an active open-source community.

FEATURES

Moving map with terrain, airspace, airports, and task navigation
Built-in audio vario for acoustic climb/sink feedback
Context-sensitive InfoBoxes with altitude, navigation, glide
calculations, wind, weather, and task data
Traffic display and advanced glide computer calculations
Task planning/declaration with support for many vario and logger devices
Flight analysis tools such as barograph, polar view, and OLC optimization
Thermal centering assistance and support for online thermal sources
Import support for common waypoint, airspace, and map formats
(including CUP, CUPX, OpenAir, and XCM)

WHY XCSOAR

No ads, no tracking, no data collection, and no account required
Works offline; your flight data stays on your device
Multi-platform: phone, tablet, PC, Kobo, and embedded computers
Open-source alternative to commercial glide computers
Supports a wide range of hardware

Documentation:

User manual: https://xcsoar.org/discover/manual.html