Letter box

There is multiple locations throughout the game where a 12x28 grid that resembles a word search puzzle can be found, this is the letter box.

The letter box code is solved by using the coordinates found on the three top rows. Each coordinate consists of an X, Y and three numbers.

Solution
The first number after the two letters indicates the number of the decoded letter in the current word. The second and the third number indicates the X and Y coordinates of the letter in the letter box and which number is used for which coordinate.

Example: is decoded as follows:


 * indicates that we use the second number for the X coordinate in the grid and third for the Y coordinate.
 * means it's the first letter in the word.
 * means it's third letter in the row.
 * means it's on row G4.

Using all this we get the letter "R"

Following this method the following words can be decoded:


 * G1 = Right
 * G2 = Person (Missing letter "R")
 * G3 = Tell

These words are used in the body message.

Zuntti confirmed this by releasing a key to the puzzle with the filename. (https://discord.com/channels/291497857725366272/361886463425642496/384658559461228555)



Outliers

 * The third letter in G1 has switched X and Y coordinates, requiring the numbers to be reversed to find the coordinate position of the letter.


 * Zuntti's signature is on the  row, starting at the 5th column.


 * contains the only number past the first three rows near the end. What it corresponds to, and its connection to the body message, is unknown. Alternatively, if one were to read it as "SONG4", it might refer to . Looking at a spectrogram shows that there is some text on it (probably "eee3 dead dead" or something similar).
 * Only the first 12 character columns of the table are used for G1 to G3, which could mean that the table is used elsewhere, too.