How to set up a new RTL language for babel using ini files?

Question

How do you set up a new RTL language for babel using the new locale ini file system?

e.g., consider trying to set up support for Classical Syriac. I started with babel-ar.ini and modified it to what I think should appear (although really I'm mostly guessing).

However, there are two problems:

1. The paragraph direction remains LTR. I can't find anywhere to set this.
2. The font Script and Language is not correctly set.

The MWE below gives this warning:

Package babel Warning: The current font is not a standard family:
(babel)                NotoSansSyriac:mode=node;script=syrc;language=SYR;
(babel)                Script and Language are not applied. Consider
(babel)                defining a new family with \babelfont.
(babel)                Reported on input line 3.

With Arabic the Script and Language are set from the contents of babel-ar.ini. I've assume this is from tag.opentype and script.tag.opentype, but it seems not to work.

The font itself reports:

$ otfinfo -s /usr/share/fonts/truetype/noto/NotoSansSyriac-Regular.ttf 
DFLT        Default
syrc        Syriac
syrc.SYR    Syriac/Syriac
syrc.SYRE   Syriac/<unknown language>
syrc.SYRJ   Syriac/<unknown language>
syrc.SYRN   Syriac/<unknown language>

What am I doing wrong?

MWE

Compile with lualatex.

\documentclass{article}

\usepackage{filecontents}

\begin{filecontents}{babel-classicalsyriac.tex}
\ifx\BabelBeforeIni\undefined
  \PackageError{babel}%
    {This file is a component of babel and cannot\MessageBreak
     be loaded directly. I'll stop immediately}%
    {Just use babel as documented.}%
  \stop
\fi
\BabelBeforeIni{syc}{%
}
\endinput
\end{filecontents}

\begin{filecontents}{babel-syc.ini}
[identification]
charset = utf8
version = 0.1
date = 2019-08-25
name.local = ܠܫܢܐ ܣܘܪܝܝܐ
name.english = Syriac
name.babel = classicalsyriac
tag.bcp47 = syc
tag.opentype = SYR
script.name = Syriac
script.tag.bcp47 = Syrc
script.tag.opentype = syrc
level = 1
encodings = 
derivate = no
\end{filecontents}

\usepackage[nil,bidi=basic-r]{babel}
\babelprovide[import=syc,main]{classicalsyriac}
\babelprovide[import=en,language=Default]{english}
\babelfont[classicalsyriac]{rm}{Noto Sans Syriac}
\babelfont[classicalsyriac]{sf}{Noto Sans Syriac}
\babelfont[classicalsyriac]{tt}{Noto Sans Syriac}
\babelfont{rm}{Latin Modern Sans}
\babelfont{sf}{Latin Modern Sans}
\babelfont{tt}{Latin Modern Mono}

\newfontfamily\sycfont{Noto Sans Syriac}[Script=Syriac, Language=Syriac]

\renewcommand{\familydefault}{\sfdefault}

\begin{document}
ܛܘܼܒܲܝܗܘܿܢ ܠܐܲܝܠܹܝܢ ܕܲܕ݂ܟܹܝܢ ܒܠܸܒ̇ܗܘܿܢ܄ ܕܗܸܢ݂ܘܿܢ ܢܸܚܙܘܿܢ ܠܐܲܠܵܗܵܐ܂

\selectlanguage{english}

Blessed are the pure in heart, for they shall see God.

\bigskip

Correct output:

\pardir TRT \textdir TRT \sycfont
ܛܘܼܒܲܝܗܘܿܢ ܠܐܲܝܠܹܝܢ ܕܲܕ݂ܟܹܝܢ ܒܠܸܒ̇ܗܘܿܢ܄ ܕܗܸܢ݂ܘܿܢ ܢܸܚܙܘܿܢ ܠܐܲܠܵܗܵܐ܂

\end{document}

Answer 1

Thanks to Javier in the comments, it turns out that babel needs all sections added to the language ini file even if they are left empty.

MWE

\documentclass{article}

\usepackage{filecontents}

\begin{filecontents}{babel-syc.ini}
[identification]
charset = utf8
version = 0.1
date = 2019-08-25
name.local = ܠܫܢܐ ܣܘܪܝܝܐ
name.english = Classical Syriac
name.babel = classicalsyriac
tag.bcp47 = syc
tag.opentype = SYR
script.name = Syriac
script.tag.bcp47 = Syrc
script.tag.opentype = syrc
level = 1
encodings = 
derivate = no
[captions]
[date.gregorian]
[date.islamic]
[time.gregorian]
[typography]
[characters]
[numbers]
[counters]
\end{filecontents}

\usepackage[nil,bidi=basic-r]{babel}
\babelprovide[import=syc,main]{classicalsyriac}
\babelprovide[import=en,language=Default]{english}
\babelfont[classicalsyriac]{rm}{Noto Sans Syriac}
\babelfont[classicalsyriac]{sf}{Noto Sans Syriac}
\babelfont[classicalsyriac]{tt}{Noto Sans Syriac}
\babelfont{rm}{Latin Modern Sans}
\babelfont{sf}{Latin Modern Sans}
\babelfont{tt}{Latin Modern Mono}

\renewcommand{\familydefault}{\sfdefault}

\begin{document}
ܛܘܼܒܲܝܗܘܿܢ ܠܐܲܝܠܹܝܢ ܕܲܕ݂ܟܹܝܢ ܒܠܸܒ̇ܗܘܿܢ܄ ܕܗܸܢ݂ܘܿܢ ܢܸܚܙܘܿܢ ܠܐܲܠܵܗܵܐ܂

\selectlanguage{english}

Blessed are the pure in heart, for they shall see God.
\end{document}