Maybe I’m stupid but I don’t see that in the abstract. I just see a GWP_20 potential for coal in the abstract. Further down there’s this table:

It seems like they’re not just counting the combustion emissions in that number.

Then there’s also this, which explicitly talks about fuel development emissions:

The carbon-dioxide emissions just from combustion are substantially greater for coal, 99 g CO2/MJ versus 55 g CO2/MJ for LNG. Total carbon-dioxide emissions from coal, including emissions from developing and transporting the fuel, are also greater than for LNG, but the difference is less, 102.4 g CO2/MJ for coal versus 83.1 g CO2/MJ for LNG (Table 4). This is because of greater energy costs and, therefore, higher emissions of carbon dioxide for developing and transporting the LNG compared with coal. Methane emissions for LNG are substantially larger than for coal, 76.5 g CO2-equivalent/MJ for LNG compared with only 17.3 g CO2-equivalent/MJ for coal (Table 4). As presented in Section 2, this result for methane emissions for coal is quite robust across regions, including China and Poland.55, 56 Consequently, total greenhouse gas emissions are 33% larger for LNG than for coal for the cases of average tanker-cruise lengths, 160 g CO2-equivalent/MJ for LNG versus 120 g CO2-equivalent/MJ for coal (Table 4).

Did you look at the paper or am I grossly misunderstanding something?