Bytran does not currently store, access or transmit personaly identifiable information.   The explanation of the bytran application permission requests and what they are used for is provided in the following.
Under the Android platform the downloaded HITRAN data and the configuration file may be stored in the "Downloads/bytran", and the calculation results in the "Documents/bytran" folders respectively.   In order to make this possible the user has the option of permitting bytran to access the "External storage".   If this permission is granted it is only used by bytran to store the downloaded HITRAN database files and the configuration file, and to save the calculation results.   Bytran does not access any files not created by bytran.   If the permission is not granted bytran will still operate as usual with the only difference in that the downloaded HITRAN data, the configuration file, and the calculation results will be stored in the application folder which is typically not directly accessible to the user.
The access to Bluetooth is used to connect to the SensorTag module (if available), and/or to initiate remote control of bytran from a remote device which may be connected to bytran over classic Bluetooth.   The bluetooth is NOT used for any other purpose (i.e. location services) besides retrieving the temperature, pressure and humidity values from the SensorTag or for data exchange using the bytran communication protocol with the remote device controlling bytran over Bluetooth.
Bytran requires access to the internet and/or local area network.   Such connection is used to do the following:
(1) A one time initialization download of the Total Internatl Partition Sums files (TIPS) from the HITRAN.org website.
(2) A one time initialization download of the molparam.txt file from HITRAN.org.
(3) A one time initialization download of the globalid.txt file from bytran.org.   In doing so the user IP address is automatically logged at bytran.org.
(4) Downloads of the HITRAN database files from HITRAN.org.
(5) To send calculation results (must be manually initiated by the user from within bytran) including over an SMS message.
(6) To carry out communication using the bytran communication protocol with a remote device used to operate bytran remotely over the Internet or local area network using WebSockets.
The app distribution platfrom providers (i.e. Google Play and other) provide non-personally identifiable app statistics and usage data which slightly varies by platform but may include as much as the following: the (1) installation / uninstallation day and time of day, (2) country, (3) phone model and (4) mobile carrier, (5) version of the operating system used, (6) version of bytran installed, (7) and the mobile phone language.   Besides other statistics the Microsoft Store also provides information about the user (8) age group (i.e. "18 to 24", "24 to 35" etc.) and (9) gender (male, female, unknown).   The usage data (when available) may include the day and number of user sessions, and their duration.