I can not guess what the reference to KDE in your question refers to (why would KDE include a TeX debugger?), but reading the log doesn't require any special tools, and is clearly independent of your operating system.
Add
\tracingonline1\tracinggroups1
so that groups are traced then
if your main file is like
\documentclass{article}
\begin{document}
\tracingonline1\tracinggroups1
aaa
\input{\jobname a}
\input{\jobname b}
bbb
\end{document}
with maina.tex being
{
and mainb.tex being
bbbb
then the log and terminal will show
This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2016) (preloaded format=pdflatex)
restricted \write18 enabled.
entering extended mode
(./main.tex
LaTeX2e <2016/03/31> patch level 3
Babel <3.9r> and hyphenation patterns for 83 language(s) loaded.
(/usr/local/texlive/2016/texmf-dist/tex/latex/base/article.cls
Document Class: article 2014/09/29 v1.4h Standard LaTeX document class
(/usr/local/texlive/2016/texmf-dist/tex/latex/base/size10.clo)) (./main.aux)
(./maina.tex{entering simple group (level 1) at line 2}
) (./mainb.tex){entering output group (level 2) at line 15}
{entering vbox group (level 3) at line 15}
{leaving vbox group (level 3) entered at line 15}
{entering semi simple group (level 3) at line 15}
{entering vbox group (level 4) at line 15}
{entering hbox group (level 5) at line 15}
{leaving hbox group (level 5) entered at line 15}
{entering vbox group (level 5) at line 15}
{entering vbox group (level 6) at line 15}
{entering adjusted hbox group (level 7) at line 15}
{leaving adjusted hbox group (level 7) entered at line 15}
{leaving vbox group (level 6) entered at line 15}
{entering adjusted hbox group (level 6) at line 15}
{leaving adjusted hbox group (level 6) entered at line 15}
{leaving vbox group (level 5) entered at line 15}
{leaving vbox group (level 4) entered at line 15}
[1{/usr/local/texlive/2016/texmf-var/fonts/map/pdftex/updmap/pdftex.map}]{leavi
ng semi simple group (level 3) entered at line 15}
{entering semi simple group (level 3) at line 15}
{leaving semi simple group (level 3) entered at line 15}
{entering semi simple group (level 3) at line 15}
{leaving semi simple group (level 3) entered at line 15}
{leaving output group (level 2) entered at line 15}
{entering vbox group (level 2) at line 15}
{leaving vbox group (level 2) entered at line 15}
{entering output group (level 2) at line 15}
{entering semi simple group (level 3) at line 15}
{leaving semi simple group (level 3) entered at line 15}
{leaving output group (level 2) entered at line 15}
{entering semi simple group (level 2) at line 15}
(./main.aux){leaving semi simple group (level 2) entered at line 15}
{entering output group (level 2) at line 15}
{entering vbox group (level 3) at line 15}
{leaving vbox group (level 3) entered at line 15}
{leaving output group (level 2) entered at line 15}
)
(\end occurred inside a group at level 1)
### simple group (level 1) entered at line 2 ({)
### bottom level</usr/local/texlive/2016/texmf-dist/fonts/type1/public/amsfonts
/cm/cmr10.pfb>
Output written on main.pdf (1 page, 9993 bytes).
Transcript written on main.log.
The error message tells you the problem is a simple group, that is { at level one (that is not nested in another group) so you can ignore all the group trace except level 1 simple groups.
Just quickly scanning the trace matching "entering" and "leaving" pairs shows that the "entering" with no matching "leaving" is
(./maina.tex{entering simple group (level 1) at line 2}
so there you have it, the unmatched { is on line 2 of maina.tex
pdflatex -file-line-error mytexfile.tex? (Changepdflatexto the appropriate command.) Seeman pdftexfor your options. – jon Sep 21 '16 at 17:50xelatex -file-line-errorworks, but I'm afraid it is useless in this case, because the message would be exactly the same. Comment out all\inputand uncomment them one by one until you find the faulty file. – egreg Sep 21 '16 at 18:11algorithm2e, which has a spurious open brace on line 1061. several people have tried to contact the maintainer, who isn't answering. here is one case where i would recommend making a change in the.sty, giving it another name (perhapsmyalgorithm2e) and putting a comment into any document that uses it to say what has been done. – barbara beeton Sep 21 '16 at 19:20algorithm2eis causing the problem here too http://tex.stackexchange.com/a/330698/13173 – Léo Léopold Hertz 준영 Sep 21 '16 at 19:34