I ran the heatmap2 tool on galaxy with the following settings:

Tool Parameters Input Parameter Value
Data transformation > Plot the data as it is; 
Compute z-scores prior to clustering > none; 
Scale data on the plot (after clustering) > Scale my data by row;
Enable data clustering > no; 
Labeling columns and rows > Label my columns and rows; 
Type of colormap to use > three; First color #0000ff Second color #ffffff Third color #ff0000;
Output format PDF;

As input file I used a simple gene expression matrix (each gene on a row, each column is a sample, 3 sample per condition, 2 conditions).

Can anyone tell me what the tool plots as output values to build the colors? Is it z-scores, LogFC or else? The color key indicates -1.5 to 1.5 as range. Thanks, appreciate any help!

As input file I used a simple gene expression matrix (each gene on a row, each column is a sample, 3 sample per condition, 2 conditions).